From the beginning, Alec has disliked Clary and is cautious of trusting her. It is soon implied
that he is rather jealous of Clary, seeing Jace's growing attraction and feelings towards her and
hates her for it.
He goes with them to Magnus Bane 's party to retrieve Clary's memories and meets the warlock ,
with whom he later ends up falling in love with. He then accompanies them to retrieve the
Mortal Cup , and in the fight against Abbadon is seriously injured saving Jace. He is saved by
Magnus Bane who comes and heals him. The two begin a secret relationship sometime after
this.