[Kamen Rider Die]

I mean, obviously the answer is Accel (dude says Henshin like he's passing a Gaia Memory), but just to have some other opinions, lemme stump for the laid-back dark reflection of Ryuki, Ryuga. I really like the way he doesn't shout "HENSHIN!", he just says "Henshin." It's somehow more terrifying when someone treats the Henshin less as a primal will-to-power, and more as a Well You Just Missed Your Last Chance To Avoid Me Killing You, by-the-by sort of thing.

[Fish Sandwich]

nobody's even mentioned Kenzaki yet smh

[AkibaSilver]

Oh wait I remembered Beast's big long drawn out "Heeeeeeeennnnnnnnnn-shin!" I change my vote to Mr Mayonnaise.

[SengalBoy]

Part of me wonders if Terui shouting henshin is to intimidate his enemies because they'd be like "Shit..... he looks pissed I picked the wrong opponent to mess with"

[Fredbob392]

I'll join th club of people who immediately thought of Terui after reading the thread title

[FairyKing]

Terui's is really iconic, it keeps the aggressive energy of riders who just shout it but is more distinct. I always wondered if he made that pause to emphasize "shin" as in death.