Poison 4 weapon

Hello, the title of the topic is such to attract more attention. Some time ago I started Loremaster and while doing quests I think in Blades I got poison from one quest. It had 5 stacks and I could apply it to my weapon. Does anyone have an idea because I couldn't find it on google but I haven't searched deeply for the name of this poison or is it a daily quest? This is awesome for PvP ;) Thank you!

it has really low dmg, around 40-60 per hit (something like instant poison), compared to high lvl poison its big crap