Take a rogue with you to scout out the first two pyramids!
We killed him with a bard, rogue, cleric, warrior, necro, and shaman (mostly Demiplane-geared). He comes with two yellow con guardians. They chain stun. We were not sure how mezzable his guardians would be, so the bard mezzed one while the warrior kept aggro on the namer and the other add and the rogue and necro burned the other add. The adds did not resist mez and could easily have been kept mezzed by the bard, or a chanter. Saarisz AE rampages under 20%. The spells he cast were curable and really not a huge problem.