Kill opponent and yourself with an equipable item

[Wolvyrne]

I'm not 100% sure if I go this right, but what I want to do is have a player find an item that when equipped will add a skill in their skillset which when used will kill the opponent in 1 shot and himself. Here's a screenshot of what I have so far:

Am I on the right track?

 

[Diretooth]

Things like this can be difficult. I once made a skill that accidentally increased the enemy's max MP rather than the character's. Based on what I can see, that attack will inflict death on an enemy twice. However, if there is an element to that that I am not seeing, then maybe someone else would be able to see it.

 

[Wolvyrne]

I used <self effect:1> so the first effect will be cast on self, then the 2nd will be cast on the opponent. Maybe I should swap the two..

EDIT: I can't test the skill yet, but I did figure out how to configure it so the skill is only available while they're holding the item. 

 

[Andar]

I used <self effect:1> so the first effect will be cast on self,

You did not say which script you used to create that notetag, so we can't tell if the skill will work as intended.
If the script you're using causes problems, you can do something similiar by adding the state with damage formula commands instead of effects