If this is the one in Mac’Aree, he is just a random spawn.
You need to collect parts to be able to summon him, not very difficult, look up WoWhead. I’d help ya but I dont have a character who’s done it anymore. :<
This dude requires 3 people to stand on one rune each Antoran Wastes.
Requires a portal thingie that you must collect Demon Eyes for, which you need a buff for, but I’m sure someone has the portal thing (Maybe) and they can just slap it up for you.
Rezira the Seer can also be reached with a toy from Timeless Isle, and a glider. The rare on timeless isle is the white/steam elemental on the bridge. It can drop a toy that’ll launch - and I mean launch - you high up into the sky, whereafter you can use your Goblin Glider Kit to get there.
Aye when going for COA my DH picked up engineering just for this purpose (ah had no packs) and seer was only one I needed. Took me about an hour or two to do the engineering quests, make the items and then cheese the boss entry. No idea how long farming eyeballs takes but my guess is much longer.