1) Standard setup for alb 5 man raid. class and role: cleric - heals/buffs. paladin - hold aggro. chase after GK when he ports. bring GK back to his spot. theurgist - dmg add/haste. petspam. keep eath pets on GK when he ports. pbt if you really want it. reaver - dps and gaurd. pulse auras when trees spawn to capture aggro, clear tree adds. merc/dps - dps. help clear adds. (could do it without a merc, but it speeds things up a lot)
anything extra speeds it up, but it also means more people to split the loot with, and may spread buffs too thin.
2) have the pally drop a ground target ("/groundset 0") at the GKs feet before you start. this is where you want to be fighting him. when he ports, bring him back to around this spot each time.
3) at certain percentages he will do his thing (I really should write those down some time. i know 85%, some percents in the middle, and 10%, 5%). he says something like "trees give me strength", teleports away to try to heal himself, and spawns a bunch of lvl 50 trees (number is proportional to the number of people nearby, so if you want to piss off a GK raid, stand around nearby witha fg and they will get twice as many adds to fight).
4) when he ports away, watch which way the earth pets run so you can chase after. other times you mgiht be able to just /face. have the pally run and go pull him back. it is advisiable to have the pally face the GK and walk/run backwards to minimize dmg (keepign in mind that the rest of the grop is busy clearing adds atm, so healing is more difficult).
even if gk heals himself up some, each % health trigger only happens once. so if you got him to 85%, and then he healed back to 95%, you dont have to worry about him porting again at 85.
also note that he has a very high parry rate. so tanks tat dont have aggro should rear positional or otherwise avoid his frontal arc (yet anntohe reason why reavers are lvoed for this).
DROPS: he normally drops aout 5 items. 1 to 2 loot and a few recharge/artificer stones. the good items being (in order of current market value): -bloodmist belt (6-8p) -shark's eye ring (5-7p) -frenzied shark tooth gem (same utility as ring, but given alb access to gobo gem this is worth a lot less) -verdant ornate ring (an ok tank ring, 1-4p)
there are a few crap items that he is just as likely to drop.
cleric - heals/buffs. paladin - hold aggro. chase after GK when he ports. bring GK back to his spot. theurgist - dmg add/haste. petspam. keep eath pets on GK when he ports. pbt if you really want it. reaver - dps and gaurd. pulse auras when trees spawn to capture aggro, clear tree adds. Scout - never misses. will out dps a merc or reaver vs GK.
forgot to note a nice trick to using theurg pets to chase GK when he ports. Theurg starts petspem 2% before port so that a pet is on the way when he ports.
if theurg uses lower level pets for this, they move slower, making it a lot easier to get one on the way. slower pet takes longer to to get to GK, ergo longer time period per pet to catch a port. if the theurg wanted to save power they could even cast these pets with a tiny gap between casts thanks to slower movement. in theory a theurg can use low level pets the whole time, as theurg pets dont hit the gk anyways, they are just there to help tanks to-hit. I normally use the lvl 32 earth pets, but in theory even the lowest level earth pets would work just fine.
the difference if pretty huge when you watch how tiny the time gap is with lvl 48 pets instead of using lower level ones.