As kayn, Depending on your form, you should either be the frontline for your team using the red form, or you should be waltzing in and out the enemy backline and killing them off.

Your Ultimate R will be on a very short cooldown now. This means that you can regularly all-in the enemy team and get free kills. Just make sure that you don't target someone who has a dash ability up.

Getting a defensive item should help you immensely, especially if the enemy team is mobile in nature. It will help you a lot during neutral, objective fights when you need to target a specific champion around choke points. As kayn, Depending on your form, you should either be the front line for your team using the red form, or you should be in and out of the enemy rear line and kill them. Your Ultimate R will be on a very short cooling now. This means that you can regularly all-in the enemy team and get free murders. Just make sure you don't target someone who has a leading ability up. Getting a defensive element should help you immensely, especially if the enemy team is mobile in nature. It will help you a lot during neutral and objective battles when you need to target a specific champion around the bottlenecks.