Widdlethorpe (-66, -1202, Stoneroot) is the quest giver.
NOTE: Missions 1-4 are the ONLY ones needed to complete this ARC. Mission 5 is only needed to get the RAID version of Korlach, the Deep Leviathan, for DoD Progression.
1. The Search for CoralEdit
To get this mission, say "Practice something smaller" to Widdlethorpe. Go to the second witheran cave, there is a tunnel to the top-left cave towards the back of the cave to find your destination. Kill the guards. Then kill the priests. When you engage the named, as his HPs go down he will spawn two adds at a time, mez the named, and kill the two adds then go back to killing the named. Repeat as necessary till they are dead. Loot the coral from the chest, and return it to the NPC.
2. Learning the PowerEdit
To get this mission, say "Practice something bigger" to Widdlethorpe. Go to the basilisk at the other side of the zone, and you will find a young witheran on the surface to your left. Use the coral you received from Widdlethorpe (must equip to use), it will charm the witheran. Fight back to the entrance of the zone, on your way you will encounter the four witheran protectors that you need. After killing all four, exit the zone to finish (do not port out).
3. Discover the secretEdit
To get this mission, say "Explore the lair" to Widdlethorpe. Collect four Basilisk Tongues, collect four witheran guts, collect four witheran skins, return to Widdlethorpe to complete.
4. Taking controlEdit
Head to the other end of the zone, past Korlach, the Deep Leviathan. You will see a drachnid with a leviathan in front of him. Clear the room. When engaging the drachnid, he will mend/heal himself to 85% at 80%-60%-40%-20% HPs, and then become stronger (hits harder), at some point, he will summon one basilisk add, which you can mez/root to keep him away from group. At 10% of its health he will heal himself a final time to 50%, at which point he will not heal/mend anymore. So finish him off to complete the mission. If you don't leave in 2-3 min, you will be booted out, either way your mission will be completed.
5. Korlach, the Deep LeviathanEdit
Enter the lair, you can reach Korlach at the basilisk cave, invised all the way, mobs are not mezzable, and are red con. Engage Korlach, the Deep Leviathan. Bring Korlach under control. Basically though, beat him down until you see an emote that he is weakened to magical influences (about every 20%), then make sure everyone stops attacking him, spam the coral stone on him (kill the adds as they pop, usually 5-6 adds) and eventually the stone will land.
NOTE: This mission CAN be done with a group even at HARD difficulty, and has been. This mission can also be done with a raid which makes the event very EASY.