"A strange Portal has appeared in the wilderness. Zombies are emerging from it! First, teleport to /warp wild, locate the portal, and then find and kill 3 zombies."
Survival Skills is the first of King Xero's quests. After you teleport to /warp wild, you will come across Lax and have the option of performing a side quest for him. Walk down the spiral staircase and approach the portal. zombies should immediately spawn from it. Once you kill 3 zombies, teleport to /warp throne for King Xero's next quest.
(Hint: you may need to kill more than three zombies for the quest to complete. If you attempt this quest during the day, the sun may kill them, and you will need the final kill)