I dunno if there has been a guide of this yet but here goes nothing~
Blood suck is a skill that damages the opponent while stealing some HP at the same time and it costs 3 stars
1st off, this quest starts in China but you need soul dodge(welling scroll quest)~ I'm pretty sure you all know where China is but just to make sure here's the region map:

Get out of the village by going south-west and go to where I there's a question mark on the mini-map.

Talk to the old geezer and he'll start showing off his skill, DOMO style
Now go back up to where there's a blue warp point

Than go here:

You'll see a white tiger threatening a villager that's on top of a cliff-thing...

Now for the fight:

Yup...I have low con and wis >,>' it was my elin that did most of the damage XD I was only there to heal since I was faster than the tigers X3

Small tigers have around 800 HP. If I'm not mistaken, top one spawns twice, middle one spawns once and bottom one spawns twice.

White tiger has 15k HP so start grinding XD
Like every quests, bring a water healer 'cause I'm starting to run low on the food I got from Q&A's riddle papers >,>'
After this is done, go back to the old man and for 3 stars, he'll teach you that skill.

it can be comboed with
its based off of attack
it can be increased with fire godess