Permanent Banish on a Unit

If you don't know what I mean by the title, I'm trying to figure out how to make my wisp permanently banished, without having to click on a skill to use it. Please help, thanks.

Action - Remove wisp 0001 from the game.

Sorry, what I meant was how do I make him permenantly banished, the skill, like the Blood Mage has.

lol, I don't think that's what he meant...

Try basing the unit on the Spirit Walker (Ethereal) found in Orc->Melee->Special in the Object Editor

EDIT: On closer inspection, it appears that the ability "Corporeal Form" is the thing you need.

just have a hidden unit case "banish" as a unit skill with a duration of 99999. if you want to do this from the beggining you can just click the ethereal box in the object editor under unit-classification

I don't see "Ethereal" under Unit Classification...

Yeah I know about the ability, range etc but where in the triggers do I find "Unit Cast Ability"? I would just use Cinematics but I want to also make him immune to physical damage, which as far as I've seen only banishment can do, and the problem with Corperal Form is that you have to click on it, and I want this to be a passive skill, which is why I need a hidden unit to cast it on him.

The actions isn't Unit Cast Skill, It's Unit - Give Order targetting Unit, and the order should be banish with the wisp as a target.

You don't have to click Corporeal Form... I just added it to the Wisp and it made it Ethereal. You can click to make yourself normal again, that's the real problem with adding Corporeal Form.

I know the "Issue Order Targeting Unit" trigger but it won't let me use custom spells, but I think I'm just going to make a custom corperal form and hide it.

EDIT: Aright, thanks everyone for replying, I got the spell to work but I had to use the original spell and modify it, I wish I could have used a custom but oh well.