Tlaloc is the evil god of rain, lightning, and thunder, and all-around pain in the neck. He was very demanding of his followers, having detailed requirements for what he deemed a proper human sacrifice (usually children). Among other things, the priests would collect the tears of the sacrificed children as an additional sacrifice the more the merrier so hideous torture preceded the sacrifice. Did I mention the sacrificed people were children? Yeah, he's jerk. If the required details were met, Tlaloc would grant the faithful the rain they sought, but on failure, hed punish them severely with drought and disease.
Tlaloc carries four pitchers of water: one filled with good water for the crops, one filled with water causing blight, one filled with water causing a freeze, and one filled with water that rots all fruit. These four pitchers are represented by a single close burst power with four different options, which makes for a complicated power. It requires a minor action (1/round only), so it will come up a lot.
Tlaloc is served by four rain servants called tlaloque, which are also provided here. Their responsibilities consisted of holding up the sky and aid in tracking the passage of time. In order to do something different, I added a rarely-seen type of power that I've used before: Each Tlaloque has a close blast basic attack, which means that a PC provoking the attack might hurt nearby allies as well. Because they looked exactly the same as Tlaloc (just small) right down to this jaguar teeth, they have a Bite melee basic attack to go along with their ranged basic attack. Still, this is a relatively simple stat block because they will appear with Tlaloc, who himself is complex enough.
The PCs will be essentially taking on 1 solo creature and 4 standard creatures whenever they face Tlaloc, which makes this a very difficult encounter to balance. As designed, it's assumed that the party should be level 30 when facing Tlaloc. You might want to level down Tlaloc if the PCs aren't optimized.
As always, your criticism is greatly appreciated.