Marisa Kirisame, the other main protagonist and youkai hunter of the touhou series, together with Reimu.

Marisa is a human witch- unlike the other powerful humans in the series, she's the one that didn't have any special talent like Reimu's spiritual powers and Sakuya's time-manupilation abilities. She's a hard worker- the only one- and the countless hours she spent learning and perfecting her magic allowed her to become an expert in the "blowing the hell out of everything with lasers" school of magic. 

Most people love Marisa, and they have a reason to. It's hard not to appreciate this cleptomaniac magician, vacant shop owner, burglar and part-time youkai hunter in her adventures lasering everyone around. If Reimu is the to-go "good guy" protagonist in dark settings, Marisa is the one in light-hearted ones (a small book-stealing habit aside). Courageous, fun and always available for a fight, she makes the perfect choice for a "happy-go-lucky" scenario.

That's not to say she's not a solid character in darker settings either- in fact, she may fit even better in those, as an egocentric, insane thief with no regards for her life, willing to anger the most powerful beings in the known world, from twisted youkai who lived for millenia to proud gods. She recklessly jumps into magic research and training, knowing that if she becomes more powerful she may become a youkai herself (of the "Magician" species- the most powerful youkai of that type being her only neighbor in the deserted forest they live in). 

And either way, most people love her. And they should- she's the one most people identify with. It's often said that she has a youkai's mind- but, with Reimu serving as the faith symbol, she's the most humane character out of the entire cast. Her desires and efforts and easily understandable and relateable- which is why she's so loved. 

And I leave you, once again, with a remix by Alstroemeria records about Marisa: