Sacrifices.

You guys, (Annabeth, Grover, You, Percy, and Tyson) were on a hunt, and came across a few monsters. There was one last one, and it came charging at Percy. He handled it pretty well, until it started to get more aggressive. Annabeth tried to help, but then.. You sacrificed to be injured for Percy to not be injured, since he was already injured enough.

Grover: "..WAIT NO-"

too late. Ya already did, and you was badly injured.