Complex sentence: When Sean met Alex, he thought of her as a government traitor and completely untrustworthy; although later, after seeing her in action, he acts as a mentor to Alex-reminding her to see past her own mission in like to bring down Semak.
Split into simpler sentences: When Sean met Alex, he thought of her as a government traitor and completely untrustworthy. Later, after seeing her in action, he acts as a mentor to Alex-reminding her to see past her own mission in like to bring down Semak.