Every squadron of Team Revolution is assigned a Sentret. The Sentret come from a large colony cultivated by Revolution, and their burrows extend all over Hamarkia. Charlie and Angel's Sentret is a wise, but temperamental soul, often giving his human companions sage advice on strategy and relationships. His civilian disguise is a Plusle suit.
Actually, no. No he does not give sage advice. He's a Pokemon. Charlie and Angel 'understand' Sentret the way Jon Arbuckle 'understands' Garfield. In truth, his little Pokemon chatter translates into irrelevant nonsense.