As seraphine, During the mid-game, your goal will be to wave clear and get lane priority. The mid-lane would definitely be better for you but don't forget to show up for skirmishes.

Use your Ultimate R very carefully, as it can be the deciding factor when it comes to winning a fight. Use the ability to CC multiple targets and chain it with your E CC.

Fights around closed spaces will help you a lot as you can target multiple champions easily. Your Ultimate R and E should be pretty easy to land.         As seraphine, During the middle of the game, your goal will be to be clear and get the priority of the track. The middle lane would certainly be better for you, but don't forget to show up for the skirmishes. Use your ultimate R very carefully, as it can be the decisive factor when it comes to winning a fight. Use the ability of multiple CC targets and chain it with your E CC. Fighting around closed spaces will help you a lot because you can easily target several champions. Your ultimate R and E should be quite easy to land.