We should have learned the Mephisto theory from WandaVision that we shouldn't create too many theories. Well many theorized that Stacy might be TwoKaizer. But it turns out, it isn't!
Stacy will transform, but into an Evil Sentai Warrior called Stacyzer. Someone also pointed out the romanization 'StaCaeser'. Let's wait for the official romanization to get revealed.
Stacy will have his own version of Geartlinger based on Gege.
Zooming in on Stacy's Geartlinger, it seems this will be called "GEARTOZINGER".
It's being pointed out that Stacyzer's mask is based on Battle Japan from Battle Fever J. Battle Fever J was once considered as the first Super Sentai Series before Toei also decided to include Gorenger & JAKQ in the series. So if Zenkaizer is based on Akarenger & Big One then Stacyzer is based on Battle Japan.
Stacyzer will make his first appearance in Episode 7 and his will attack Kaito by summoning past Sentai Teams and their Robos.
Ending of Episode 6 had revealed that Stacy is the son of Barashitara. But how is that possible? How can a Kikainoid have a Human Son? and I thought Barashitara would just be a side character. Looks like there is some yet to be known stories among these characters.