Storm Shadow Allegiance In GI Joe 2 Revealed
 

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So the actual answer feels kind of...lacking? It's kind of hard for me to describe my opinion on this without revealing potential spoilers.

I thought Storm Shadow was killed, like hardcore, in the last on?

Also, it looks like C-Tates get killed early on from the trailer and they didn't bring Scarlet back and that make me sad.

No, Storm Shadow was beat down pretty good but fell into the Artic waters before he was actually "killed". He was instead assumed dead since there was no body to be found. It's a stretch, but theoretically the ice water could have kept him from dying by basically putting him into a cryogenic state until CC or some other Cobra goon scooped him up.

In this continuity CC is a doctor, after all. ;)

As for Duke, the trailer does not explicitly show him getting killed. It's mostly fan speculation due to the Rock's lines about "we're all that's left". Duke could just be put into a coma, like in the G.I.Joe animated movie.

It is a real stretch but I didn't think killing off a fan favorite character made much sense. I guess I can suspend my disbelief for a franchise that has always been far from grounded in reality.