User blog comment:EliteMadness/Custom Champion - Vane/@comment-7709681-20190215233433/@comment-4091261-20190217143159

Well, I might as well throw my suggestion for the ultimate.

Following up on the "explosions could be this champion's ultimate" think about this: a C4 Charge. It would be an untargetable stealth trap that would knock up everyone in a massive range, but it would need to be manually activated.

Now, I know that and  exists. However, having similar ultimates is by no means uncommon. There are just different spins to it. The difference between this trap would be that it is not merely a spammable trap. It is a single-use ultimate grade trap.

Why would he have an ultimate like this? Well, for one, it meshes well with his choices. The other reason is that it actually gives a reason to why the hell he should have a : to bait people into the blast zone.
 * This is a scientist so he knows how to make his own explosives.
 * This is a modern day assassin, so using C4 is not strange at all.
 * This is untouchable, so using a trap to delay the enemy is to be expected.

A manually activated knock-up explosive untargetable stealth trap is already unique to have as an ultimate as is. You could try to make it even more unique with his passive if you really want to go crazy with it, but I would consider that overkill.