Severant is in a much better mood this time and has agreed to train you further, but still felt he had to offer some challenge for you to prove your worthy. Forest Oastics are a bit less odd looking than the Lava Oastics you fought earlier, and shouldn't be all that hard to defeat. They are most commonly just south of Demon's Peak near the Eastern Outpost.
Forest Oastics that make their home in the Yew Forests west of the Eastern Outpost. Defeat twenty (20) of them and return to Severant for more training.
Return to Severant in Dralk to be trained in the next rank of Drain Strike
(When accepting the quest)Severant: I apologize for treating you as I did the last time you approached me for training. We are all given different roles in life, and mine is to train others in how to drain the life from enemies and use it to heal yourself. Your Drain Strike ability is an important one in your arsenal, and I should have recognized that. I still, however, must test your worthiness before I can simply train you in this ability further. So seek out the Forest Oastics that make their home in the Yew Forests west of the Eastern Outpost.