Sceptile
Sceptile's been a powerful and consistent threat for all of BW2 RU and the majority of BW1 RU as one of the if not the best Grass-type in the tier, and never fails to put pressure on the opponent when its on the field. Both Sceptile's special and physical sets are very dangerous, but most importantly they actually beat each other's checks and counters quite handily, meaning that any opponent facing Sceptile needs to effectively scout it, as their gameplan could easily be stopped by a Swords Dance Sceptile using Acrobatics on their Roselia or something similar. This alone is enough to show how scary Sceptile can be. Sceptile also has one of the highest unboosted base Speeds in the tier, which makes it that much harder to deal with and that much more worthy of titan status. Not just did this Speed make Sceptile harder to deal with, but as Swamp Rocket mentioned it was also the barrier of entry for most Choice Scarf Pokemon, and anything slower than Sceptile after the Speed boost was rendered bad at the role, showing how it affected the metagame a bit. All in all, Sceptile isn't quite as powerful as the other titans imo, but its versatility and consistent presence make it worthy of the #10 spot imo