Thanks to Voldigar for getting us this description of the fights for the world bosses. If you sign up for the World Boss Runs (check guild calendar) this is a great place to get an idea of the fight before the event!
(1) Tarlna the Ageless
This world boss spawns in southern Gorgrond, near Bastion Rise. He drops ilvl 650 Chests, Belts, and Gloves.
• Do not stand in front of Tarlna to avoid his frontal cone, Colossal Blow. Healers should also be ready to use cooldowns for the raid damage portion of this ability.
• Stay spread for, and be ready to heal people who are afflicted by, Savage Vines.
• Just like Yalnu in The Everbloom, Tarlna will spawn a field of sproutlings during Genesis. Run over them to stamp them out.
• If the sproutlings are not stamped out by running over them, they will evolve intoGiant Lasher. These adds cast Lasher Venom and should be killed quickly.
• In addition to those adds, Tarlna also spawns Untamed Mandragora which should be tanked and killed. They spawn pools of venom through Noxious Spit. Don't stand in those!
(2) Drov the Ruiner
This boss spawns in central Gorgrond, just north of the Gronn Canyon. He drops ilvl 650 loot.
◾Do not stand in front of Drov during Colossal Slam and healers should be ready to use cooldowns during this for the raid damage portion of the ability.
◾Raid-wide damage also happens during Giga Smash, so use cooldowns or personals then as welll.
◾Drov will periodically cast Call of Earth which awakens Frenzied Rumbler. These Goren adds should be killed.
◾Do not stand in front of the Goren adds due to Acid Breath and watch out for their Crushing Charge.
Rukhmar spawns in southern Spires of Arak. She drops ilvl 665 Legs, Boots, Rings, and a Mount!
◾Much like her fight in Skyreach, you will have to watch out for the Piles of Ash that the boss creates.
◾Avoid the Piles of Ash due to Blaze of Glory. This will reignite them if you are within 5 yards of a pile.
◾When the boss flies in the air, healers should be ready to heal the random raid damage from Loose Quills.
◾Throughout the fight, Blood Feather will cause Rukhmar to spawn phoenixes that fixate on players. Run away from the phoenix that is fixated on you.
◾Players should kill each others phoenixes away from the Piles of Ash so they do not reignite.
◾Tanks will need to tank swap due to Pierced Armor and Sharp Beak.
◾Energized Phoenixes fixate on random players, but Depleted Phoenixes can be tanked normally.
◾Tanks should face the boss away from the raid at all times due to Solar Breath.
◾Healers will need to keep on top of the constant raid damage from Solar Radiation