I soloed the Yagudo Avatar twice but haven't seen this staff. It's fairly easy to kill it seeing as it's only a smn. I kill the High Priest and Templar with ease and sometimes the Avatar is up there too. If you take out the High Priest and templar, then pull and kill the pet while the Avatar has it's back turned, you can fight then it without the pet as it takes awhile for it to call forth another one. Yes, it will Astral Flow and call another Prime like Garuda, Leviathan or whatever but that never kills me anyways. Just thought I'ld throw in my experiences as a 75thf/nin. GL
Well, he's level 75, and in an exp party you fight mobs that'r like 7 levels higher than you. So I highly doubt a party of 60-62 could touch him, let alone kill him. And he'll summon a random Avatar and use their Astral Flow ability when he 2-hrs (usually around half hp). The Judgement Bolt you saw was just Ramuh being evil...
This NM is a nasty AOE called judgement bolt it took 650-720 off the whole party. Our party easily beat the high preist but this guy was insane. we had HLs too but most of us were in the 60s. leave him alone