This is such a unique and fun group of creatures to add to your campaign. My group really enjoyed the fact that it wasn't your normal, run of the mill monster encounter. The lair/environmental effects provide some great flavor, and the creature abilities (just wait till you get to use the Hagasus' Crushing Confession!)

But don't just toss them in as battle fodder, really play them up as the mix of good and evil, the internal battle for control. Those RP mood swings make for some great and memorable encounters.