Aegislash is probably the most used pokemon at the moment(?), Its an extremely predictable but potent pokemon, as it can achieve 3 goals all at the same time.
- Sweep
- Wallbreak
- Pivot Switch
It's not a tank, and should not fit that role. It may be able to sponge one attack, from an offensive pokemon. But other than that, it can be 2HKO by a few common pokemon.
It has a favourable matchup against almost every pokemon in OU, due to its typing/move coverage/stats. Kings Sheild is pure bullshit. The actual move, isn't terrifying, BUT the idea of having it is. Playing against Aegislash you always have to have Kings Sheild lurking in the back of your head, for even strong offensive pokemon like Excadrill and Talonflame have to fear their ATK dropping by x2. Aegislash can pretty much synergize with any pokemon due to its amazing typing and stats. Kangaskhan is probably the most obvious. I highly reccomend you whore out this pokemon as much as you can, there is absolutely no good reason you should not use this pokemon if its allowed.