754 Lurantis

Razor Leaf benefits from STAB to deal significant damage, but in return ties for the lowest energy generation in the game. Fury Cutter gives up meaningful damage output in exchange for very fast energy gains, letting Lurantis use its Charge Moves more often.

Leaf Blade is one of the best and most efficient Charge Moves in the game, benefits from STAB, and can be used frequently with its low energy cost. Leaf Storm is a less consistent option due to its much higher energy demands. Superpower provides wide Fighting-type damage, though the lack of STAB and a difficult self-debuff makes it difficult to use. Alternatively X-Scissor could be chosen for very niche and specific circumstances, but is generally not recommended.

Lurantis is a pure Grass-type Pokemon with access to the highly valued Leaf Blade. While its bulk isn't particularly notable, fast access to valuable coverage is extremely desired in the meta. Fury Cutter is generally recommended for more consistent access to Superpower, which is much needed against popular Steel-types. Unfortunately Lurantis is very easily walled off by almost anything that flies in the air, and it's very unfavorable against most Poison-types as well. 

XL Candy is required for Lurantis to reach the CP cap of Ultra League, making this Pokemon somewhat expensive to invest in. Interestingly enough, Luranits sports a very useful moveset against common Dark-type Pokemon in this league, though still falling short of beating Mandibuzz. Just like in Great League, Flying-types and Poison-types make up the bulk of losses, so as long as those are covered Luranits can be expected to do well against the overall meta. 

Luranits could pull off a surprise win against unsuspecting opponents, but is generally not advised due to its lack of stats.