This seems approvable with just a few, small modifications. For one, since it's a kido, it needs to be from reiatsu, so adding in that the lightning bolt is made of spiritual energy is important. Along with t hat, there should be a bit more of a definite term for how the bolt works. Essentially, I'm asking for more details. Saying that the bolt is entirely based on tier negates the fact that there are skills and such. If the bolt strikes and a person doesn't have a good enough defense to defend, then I think it should have a base stun for a single post is the target is a full tier underneath, if they're equal or higher, then it could be a slow to deduce a tier from their speed skill. This is an ability that seems fine, just needs a bit more description, so add what you think is good in and it should be fine. Remember, this isn't magic, but a shinigami using spiritual energy to create an effect.