[b]Archmage MC[/b] I'm going to have to go with no. It's very interesting but portals in general should be difficult to create. Even harder to control is such a precise way. Every portal in the bleach world requires a lot of effort to open. This includes garganta and senkaimon. Even though those are portals to separate realms, they need a lot of energy. So something like MC's ability would only be able to be used once every few hours or so and would appear in a general area as directed by him. Beyond this, the portal would always be around the same size and require energy to maintain for longer then a few minutes. Also lets just assume for better or for worse that a portal would never appear on top of anyone.