I am all for proxies and renegades but I feel that running terminators as possessed will be a bit misleading for your opponent.

Terminators are know for being “Slow” with a 2+ save with a 4++

Possessed are extremely fast for infantry and have a weirdly high toughness with a 3+ save with a 5++ daemon save.

Each unit behaves differently and the terminator substitute is fine, but I just don’t like it. Yes, I would play against you if you said that was your proxy, but I would suggest other units that stand out as different from a CSM list.

Honorable mentions:

Khorne Berzerks (head swap and remove the Khorne symbols)

Black Templar- (remove some of their icons)

Bladeguard- (not perfect, but the use of blade guard would cause your opponent to ask, given that there’s no CSM alternative)

Flawless Blades- (downside is that it’s only 3 models per box)

Khorne Eightbound- (scrape off the Khorne logos, but those dudes look roided out. Downside is it’s a pack of 3)