While Super Sentai has as a major theme the concept of the power of several people who fight together and manage to do together what they can't do all alone (the power of teamwork), in most sentai series, the hero and iconic character of the series is the Red ranger. Indeed, while each of the rangers get some focus in their series, usually, the main character, the one who has the most focus and gets the most story material is the Red ranger. Indeed, the main stories of most sentai series either involve Red, or the team as a whole.
However, in some series, other rangers might get either major storylines, or almost share equally the focus with Red, or even in a few cases, be more involved in the main plot than Red.
Let's review the sentai series during the different eras of sentai
1) Early sentai (Uehara era and early Soda shows (Gorenger-Dynaman)
During that era, the shows were very episodic, without long running arcs (Dynaman had the Black Knight arc during its last 15 episodes). As such, while Red was the iconic ranger, the focus was more on the story of the week, with the focus characters being the ranger (or rangers) who was the central character of the episode and the guests of the week, child or other. During that era, each ranger had the opportunity to shine in focus episodes, and other than being the leader, the Red Ranger didn't overshadow the others much, even if, as the leader, he was the main hero.
Interestingly, in a lot of cases, during the final arc, the mentor character had the opportunity to shine, such as General Kurama in Battle Fever, Arashiyama in Sun Vulcan and Yumeno in Dynaman.
The most extreme case of stealinng spotlight mentor was of course Banba/Big One in JAKQ Dengekitai who was over the top, getting the most fun lines and plots during the second half of the show, being played by Hiroshi Miyauchi, and being pretty much Zubat v2. Bonus points for being himself a ranger and becoming even more iconic than Space Ace.
2) Soda era
Starting with Bioman, Super Sentai started to have some long running arcs, notably involving rivalries between heroes and villains. Once again, the usual pattern was Red being the main hero, the other rangers getting focus episodes, usually fillers, but, mostly the storylines involved mostly the heroes as a whole and their rivalries with the enemies.
Some noteworthy cases where heroes other than Red had the opportunity to shine in major plot episodes :
- Flashman : a major plot involved one of the heroes being the missing child of the Tokimura family : the one who ended up being that child is none other than Yellow Flash, Sara : sha also ended up being the one who made the first the decisive choice of destroying Lee Keflen's Synthetizer, who was responsible of so much evil in the universe.
- Maskman : Akira was the one involved in the Fencer Unas plot, turned evil against his will, with the plot climaxing in exposing Igam as a woman
- Liveman : the one who has the final confrontation with Bias is not Yuusuke but Megumi, even if Red Falcon has most of the focus in the final arc.
3) Jetman Sugimura era
Interestingly during that era, plenty of shows allowed other heroes other than Red to have plenty of focus
Jetman is an interesting case, since for the first time, it can be argued that the show has two major protagonists : Ryu/Red Hawk of course, but also Gai/Black Condor as well. Indeed, most of the main arc episodes involves the difficult relationship between the professional soldier and the lonely rebel, which evolved into a strong and sincere friendship. Black Condor becoming pretty much the the deuteragonist of the show, the one who had the most character development and arguably the most popular character of the show was certainly linked to its popularity with the audience and Inoue's personal tastes. It's very telling that the most iconic (but also controversial) element of Jetman is actually involved Black Condor and his premature death at the very end of the show.
Zyuranger started the tradition of having additional heroes who become major characters as a core concept of sentai.
As such, in Zyuranger while the main character is Geki, the red hero, the one who ended up being the most iconic character, and the one who had the most core plots was in fact Dragonranger Burai (the additional green ranger). Most of the key plot episodes of Zyuranger involved him, with the first Dragon ranger arc, and of course, his death arc. Because Burai was Geki's older brother, the Burai arcs did also allow Geki to get some spotlight, so he still was able to keep his status as main character. However, Zyuranger has two iconic ranger heroes, Geki as Red and Burai as Dragonranger.
Dairanger is also an interesting case, since in that show, each ranger was given a storyline for himslef of herself, to allow each one of them to get some spotlight.
While Red was still the main hero and managed to get the most spotlight, two other heroes had major storylines involving long running plots lasting more than two or three episodes : Kibaranger Kou, with his quest to find his mother and his rivalry with Akomaru (like Dragonranger, he had two major long running arcs in the show) and Daigo/Shishiranger, who had his tragic love story with the beautiful Kujaku, with Gara as their main enemy.
Kakuranger is another striking case, having not Red, but White (who is also the girl of the team) as the leader. Sasuke/Red and Tsuruhime/White are pretty much the two protagonists of the show, each getting plenty of focus arc episodes, Sasuke being the major rival of the Kunoichi team (in the into arc of the evil cat -turned into women ninjas and the Daradara arc, where he meets Taro And Jiro, the companions of Tsuruhime's father), and Tsuruhime having her storyline with her father.
4) Takatera-Kobayashi era
During that era, most storylines involved the team as a whole, with Red getting the most focus.
However, two shows, both written by Kobayashi, deserve some focus :
Gingaman : while the storyline mostly involved the Gingaman as a whole, it's ineresting that several rangers other than Red get some long running arcs :
- Gingagreen Hayate has his rivalry with Shelinda, Zehab's second in command
- Gingablue Gouki has his love story with the lovely teacher Mrs Suzuko
- Kurokishi Hyuuga has his long running plot involving Bucrates
Timeranger : while Tatsuya/Timered is without a doubt the main character of the show, others heroes also had opportunities to shine
-Naoto/Timefire is without a doubt the one who got the most focus : as the one being involved in the City Guardians, and the only Timeranger who worked with the official foces fighting the Londarz, he got plenty of focus during the second half of the show, notably showing his rivalry with Tatsuya and his ambitions to get power within the Asami group.
-Among the core Timeranger, Timeblue Ayase had his disease being a major storyline during his focus episodes, climaxing in episodes 40-41. Domon/Yellow had his love story with the young journalist Honami, and Yuuri/Pink was the one who had the most personal grudge agains the Don Dolnero, the leader of the Londarz.
5) Experimental era : Gaoranger-Gekiranger
It's during that era that the two shows who arguably gave the most focus to non Red heroes appeared. In those two shows, unlike most of the previosu cases, not only those heroes get major focus, but the Red hero sometimes feels like he's a supporting character instead of the main protagonist :
Hurricanger : in that plot heavy show, it can be argued that the heroes who get the most focus in the main storylines are either the Gouraigers or Shurikenger
Indeed, in the first third of the show, the Gouraigers are pretty much the main focus, as soon as they appear, with them trying to become the most powerful ninjas. During that era, they are behaving like antagonists, opposing the Hurricangers, usually with the help of the Jakanja, but actually having their own agenda. The climax of that arc is of course them realizing the errors of their ways, realizing that their quest was the result of the influence of a cruel father, and of course, the importance of protecting Earth from the Jakanja. During the second third of the show, the main arc was mostly the rivalry between the Gouraigers and Manmaruba, and the struggle of the Gouraigers to become true heroes. They had both to deal with Manmabura's cruel revenge against Kabutoraiger, planting a pace scorpion in his body and their remorse about their past actions and their relationship with the Hurricangers. It's also during that arc that a major new ranger, Shurikenger appeared. With his Over the top personality, his gratuitous English and his running gag of being played by past sentai actors, he quicky managed to steal the spotlight. That second third of the show ended up with the defeat of Manmaruba , Shurikenger releasing the Revolver Mammoth mecha and the Gouraigers managing to become real friends with the Hurricanger.
The final arc gave most of the focus to Shurikenger, focusing on his tragic backstory, his torn loyalties between his friends and the lady he had sworn to protect, Gozensama. At the end, the latter met a tragic end and Shurikenger shortly afterwards sacrified himself to help the Hurricanger in Gouraigers.
It's striking how in that show, the major storylines give plenty fo focus to non Hurricanger heroes, and while HurricaneRed is the one who should be the main protagonist, most of the plots involve mostly other heroes.
Abaranger : Another striking case : it can be argued that the main character of Abaranger isn't Abared but actually Abareblack. Indeed, most of the core plot episodes involve Asuka/Abareblack's story, and Abaranger's main plot can be seen as Abareblack's quest to defeat the Evolian, who plagued his entire life, as well as reuniting with his wife and daughter. As the one who came from Dino Earth, the one with the longest story with the villains, and of course, the one who had the strongest rivalry with an antagonist (his rivalry with his brainwashed wife Jeanne/Mahoro).
Actually, when the major storylines don't involve Asuka, they involve another ranger, the evil Abarekiller Mikoto Nakadai, and starting with episode 18, the main plots either involve Abareblack or Abarekiller. Abared manages to get focus however, because he's the main rival of Abarekiller (and because he has a cute kid :) )
Other than those two cases, during the experimental era, non Red rangers are often able to get focus, especially if they have an antagonist role. Two other shows involve antagonists ending up becoming "Bangai heroes" rangers
Wolzard is a major antagonist of the show during the first 34 episodes, seemingly killing the heroes's mother, being a fierce but honorable enemy to the Magirangers, especially Magired, opposing them, but also wanting them to be strong, instead of killing them when they're weak. It is revealed that Wolzard is actually the heroes's missing father, the hero Blagel, who ended up being brainwashed by the evil N'Ma after a failed expedition against the Infershia. Blagel was actually a major hero among the Heavenly Saints who opposed the Infershia. And indeed, once freed from N'Ma's brainwashing, he fought the Infershia as well, even killing one of the Ten Gods of the Pantheon, Wyvern, after becoming the good Knight Wolzard Fire.
Magishine also got nice focus. As an Heavenly Saint, Sungel, he was a companion and pupil of Blagel, and he's the one who has the big rivalry with Meemy, who is the traitor Ragiel. He ends up being the one defeating Meemy, who was the main antagonists during the second third of Magiranger.
While Jan is without a doubt the main character, who gets the most focus, if Rio and Mele can be seen as rangers as well, they also got plenty of focus as the main antagonists with Rio being the dark counterpart of Jan. Actually, Gekiranger is pretty much about their different paths after a similar tragic past (both lost their family in a tragic way). In a way, Rio can be either seen as a main antagonists, or as an anti-heroic deuteragonists, with Long being the true antagonist.
6) Modern era (Go-onger and beyond)
During that era, all shows had the classic pattern of "plot involving the whole team, with Red getting the most focus".
Two shows deserve some focus :
- Gokaiger had Blue having an arc involving his past as a Zangyack soldier, who escaped the Zangyack after realizing their cruelty, and his realization that his best friend was turned into the robotic Barizorg, losing all his personality.
- Kyoryuger is a very interesting case : while Red is the one who gets the most spotlight, it had plenty of arcs involving other rangers; indeed, while Daigo was the main hero and stole focus in almost every episode, other rangers also had some storylines involving rivalries with villains :
- Torin: the mentor of the team, who would become Kyoryusilver is himself a former Deboss, Chaos's younger brother, and many episodes deal with the rivalry between the two brothers. In fact, Kyoryuger's storyline can be seen as the conflict between the two brothers, Torin the one who protects, and Chaos, the one who destroys. Besides, Torin had also his friendship with Daigo's father.
- Utsusemimaru/Kyoryugold : his backstory involves him being trapped by the evil sentient armor Dogold, and after being freed from his evil influence, Gold still had a rivalry with him
- Ian/Black has his rivalry with Aigalon, who killed his friend and stole the gem he had found (who ended up being the key to awaken Bragigas), and several episodes show the rivalry between the two.
- Nossan/Blue had his storyline with his family, notably his sister (who would end up becoming the second Cyan), and his rivalry/friendship with Candelilla.
However, those storylines (except Torin's) usually didn't get the focus they deserved because the show did everything to have Red get the most focus he could.