Since season 7 has been using a tank meta and with very mobile fighters like Camille, Lee Sin, and Yasuo being frequent picks, Sej has become a great support. Since she is a tank who is naturally armor heavy she is great for taking hits from an adc while fully utilising slows, knock ups, and heavy crowd control. During and after laning phase, she is great for her initiations and since we are building her to be highly mobile, she can help any lane and prevent the enemy team from running.

The only part of her masteries that I would suggest varying is maybe switching Bandit for Greenfather's Gift depending on your personal play style for a pokey support.

Pros
- high CC
- high mobility
- great initiation

Cons
- limited when stuned or slowed
- low kill potential
- must buy items efficiently