Gunblade Trigger spell

Roughly pls tell me how to do this spell.

It has a 15% chance to trigger on the enemy on each attack.
When it triggers on the enemy, it creates a sound and a certain animation for 1 sec.

When the player uses the ability gunblade trigger [Hotkey R], the gunblade trigger occurs and deals bonus dmg plus 2second stun on the enemy.

Point is gunblade trigger can only work if the player uses the ability gunblde trigger [by pressing R] during that 1 second window of opportunity.

How do i make this? I know how to do the sounds and animation, just not too sure how to do the main part. I think its gonna have to involve buffs. Some guidance pls, thank you

I believe it can be done via triggers, i need a passive/active which has a 15% chance to put a buff on enemy, and it deals bonus dmg and stun ONLY when the ability is triggered while target has buff. This and i am gonna add renzokuken ultimate lol. I wonder which base ability does that put buff on enemy 15% chance.

Can you please fix your grammar and description? I have very little understanding of what it is you need...

You need 1 passive ability that has a 15% on attack to happen, right? And then a separate, active ability that can only be used within 1 second after the passive activates?

Try using Bash or Orb of Slow.

I need an ability that is such that when u attack, it has a 15% chance to inflict a buff on the target. And when i activate an ability, it deals dmg and stuns all units that has that buff.

hmm orb of slow, Thanks i will try

Make the ability based off of acid bomb with a custom buff, and make the buff last 1 second while making it do 0 damage (Also, change the AOE to 1 so it just affects the main target)