Like Reimu, she can summon Japanese gods to use their power. However, unlike Reimu, she uses Lord Enma's powers instead of the powers of Gensokyo's native gods, since Lunarians don't follow Gensokyo's gods. She is also more capable of summoning properly, while Reimu isn't trained enough to do so, as stated in a panel in Silent Sinner in Blue, Chapter 17.
It seems she uses a sword to paralyze enemies during an invocation.
She earned some notoriety for single-handedly defeating four of Gensokyo's finest without breaking a sweat and having just been introduced to spellcards (not to mention blocking a Final Spark with her sword).
The chosen names for the Watatsuki Sisters make a direct reference to the family history of the Dragon God, who can be referred to alternatively as Ryujin or ‘Watatsumi’. Individually, the sisters may refer to the Dragon God’s daughters, Toyotama-hime and her younger sister Tamayori-hime. Considering the events that were revealed Cage in Lunatic Runagate Chapter 3, it can be rumored that many of the legends about the Dragon Palace in fact took place on the Moon. Whether or not the locations are one in the same is unknown.
She's depicted as a tsundere officially, as in Inaba of the Moon and Inaba of the Earth Chapter 26. Yorihime said that she came to Eientei just to make sure Toyohime goes back. But the truth is she's afraid to be left alone and followed Toyohime instead.