Converting Energy Drain for 5e

[Azurewraith]

So im in the process of converting a vamperic ilithid(Lords of madness P160) from 3.5 to 5e now most of it is fairly straight forward however i am utterly stumped by its energy drain ability which bestow 2negative levels and increase the ilithids HP. I am unaware of negative levels in 5e would i be best just doing a straight conversion or just losing the negative levels and keeping the temp hp?

Any ideas would be great thanks

 

[jodyjohnson]

Drain Life like a wraith (one of the original Level drainers) combined with Vampiric Touch for the Temp. HP.

If it is really serious have it grant Disadvantage on saves, checks, and attacks until the target saves it off. But I think the reduced max hit points is pretty serious already.

 

[Azurewraith]

Brilliant thanks i should of looked harder i guess -.- not left my self enough time now im rushing