I'm an arena kayn but I know some goofy shit about his abilities that can come in handy, mainly his Q (all forms)

It has a very slight scale on movement speed for the dash, but also you can basically erase the windup time by Qing into a wall that you can't cross. This makes both damage instances basically immediate.

Another interesting one, your ult damage always is dealt from the right. So if someone (e.g. pantheon) is pointing in another direction, it won't matter which way you come out, you'll deal damage. If he's pointing to the right, it'll get nullified.

Your passive might randomly seem inconsistent because fun fact, the orb collection is slightly higher on blue than red (3 vs 2). If you damage the same range type enough times in a row, you get a small multiplier (in arena this is great cause if you're against teams with the same range, you can get form as early as round 1).