jack krauser
A psycho like you can't bring order or balance
JACK ATTACK! Okay. Sorry about that, I just wanted to say it. Anyway, Big ol' Jackie boy and Leon go back when Leon was training to be an American special agent. The two were training buddies and they seemed to be good friends back in the day. Randomly one day, it was reported that Jack got involved in a freak accident of a helicoptor crash and ended up dying. This information becomes false when Leon discovers that Jack is still alive in RE4. Apparently Jack faked his death and started working for Wesker and also for Saddler to create false trust with him to get information for Wesker. Jack's job during the whole time was to get rid of Ada and Leon once and for all. Leon ends up fighting him multiple times and then Ada ends up putting the finishing fight with Jack and his creepy arm.
So was Jack and Leon ever truly friend's in Jacks eyes? Obviously not. It seems Leon gets decieved a lot and this incident was no different. Poor Leon must have some major trust issues.
