User blog comment:SayuriDarling/Full first chapter of The Mark of Athena/@comment-184.58.22.209-20120610200321/@comment-5175468-20120701010411

Annabeth is already confirmed.

Percy and Jason because Jason is the team leader and Percy is almost like second-in-command (I guess?) and they are both very powerful and they are both leaders from CHB and CJ.

Either Leo or Hazel for the whole Sammy-Leo thing.