Technically speaking, poltergeists are not yuurei, but there are no other appropriate classifications for them so they are described here.

Merlin Prismriver is the middle sister of the Prismriver Ensemble(*1), and her forte is the trumpet.

She is the star of their performances, standing out the most.

She has many fans.

She looks just like a human.

Of the three sisters, she is the tallest and her hair is the brightest, and she often takes center stage at live events.

The trumpet she holds is said to be the yuurei of a fearful trumpet that's taken the blood of many jazz trumpeters(*2), but it's unknown if this is true or not.

It is unclear how a trumpet would suck the blood of the living.

She has an incredibly cheerful personality and is never seen depressed.

She's known to sometimes blurt out incomprehensible words.

The sounds she creates are sounds that uplift the spirit.

People who are overly influenced by her sounds will do things such as break out into dancing, or become unable to hold a coherent conversation.

It might be perfect for those suffering from depression.

Usually the Prismriver Sisters perform as a group, but Merlin can also be seen acting independently.

It seems she holds solo concerts, but going to see such a performance may be dangerous for the reasons outlined above.

1: See the article on Lunasa Prismriver.

2: They say this at the beginning of their live performances.

"On my way to the lake, I could hear the sound of brass instruments from far off." (Anonymous)

It was thought to be the sounds of Merlin practicing.

It may also have been a call for a tengu assembly.

"I went to see one of her solo performances, but it was a brass ensemble. Most of the time, it wouldn't be possible for one person..." (Cheerful ghost)

The instrument she uses is symbolic, so you shouldn't think that sound actually comes out of it.

It's not well understood where the notes actually come from, but since they seem to actually be the yuurei of notes, they probably come from close by.

"What? Merlin isn't the leader?" (Anonymous)

She isn't human, so something horrible might happen to you if you say things like that too often.

She is very friendly to both humans and youkai, so you have nothing to fear from her.

However, it's hard to hold a conversation with her alone, so refrain from talking to her if you see her alone.

As a phantom, her behavioral principles are different from those of humans, so while it's not impossible, mutual understanding is very difficult.

It would be unfortunate to say the wrong thing and have her misunderstand you as spoiling for a fight(*3).

The Prismriver sisters themselves are fairly powerful, and the Prismriver Ensemble has many fans, so there is little hope of winning if you cross them.

In addition, the sound of a trumpet can carry quite far, so if you happen to hear it from far off, take care not to listen too closely.

It can affect your spirit.

3: Such misunderstandings are common due to difficulty in communication. Even praise can be dangerous.