#serintsu

In Houlen, "hou" (鳳) refers to the Fenghuang (鳳凰), a bird in Chinese mythology said to be the king of all birds. It is often paired with the Yellow Dragon to represent the Emperess and Emperor and China respectively.

Although rarely used on its own, "ren" (聯) carries the meaning of "link" or "pair". Perhaps used in reference to the title of the entire series "connecting chain".

In addition, "houren" is also the reading of 鳳輦, which refers to a type of palanquin decorated with a Fenghuang on the roof, used specifically by the Emperor. Nowadays it also refers to the same type of palanquin used in Shinto shrine processions as well.

In "Yabusame" (藪雨), "yabu" (藪) means "grove while "same" (雨) means "rain". Read together it refers to the Asian stubtail, given this name as their cries are said to sound like rain pattering on a grove.

Curiously enough, while Yabusame's name is indeed a Bird's Name, they are the only character so far with multiple birds in their name that are not related in any way, literally or through wordplay.

Titles

Yabusame is one of the few characters to have two titles. First, their default title: Flawless Thoughtlessness (天衣無縫の能天気)

天衣無縫 is a phrase that literally means "a celestial's clothing has no seams", which refers to something that is naturally flawless with no trace of artifice. So this is where "flawless" comes from.

能天気 refers to an easygoing person who never thinks deeply about anything, which is where we get "thoughtlessness from".

In their chef form in BotC, they're titled Chef Unbound in Any Direction (縦横無尽な調理人).

縦横無尽 literally means "vertically and horizontally endless", and refers to someone who acts freely and as they wish, hence "unbound". 調理人 simply means "chef".

Basis: Dimensions and String Theory

Similar to fellow protagonist Tsubakura Enraku, it's difficult to identify any particular figure, historical, mythological or otherwise, in them. However, it is fairly clear that Yabusame is based on dimensions and string theory.

Dimensions

Yabusame's most obvious tie to the concept of dimensions is their ability, "something like crossing dimensions". While Yabusame is indeed shown to be able to do so, like in BPoHC's tutorial where they crossed into an alternate Mugenri, how this is achieved is unclear.

Curiously, JynX personally considers Yabusame's ability the most dangerous in the series so far, although the reason remains unexplained.

The most common application of Yabusame's ability is their "hyper-dimensional pockets", portals that connect two different dimensions. They use them to send and retrieve things to and fro between dimensions, an example being their spell Confused Origins "Screen Shuffle", as seen below:

There are a number of possible curiosities possibly related to Yabusame's abilities, such as:

Yabusame is apparently only "technically human", whatever that means

Suzumi's abilities seem to have next to no effect on Yabusame at all, and even if they rewound time after killing them it would apparently still leave them dead, according to Suzumi

While Yabusame seems to have free control over their ability, EE's bad ending would imply that they need to fall asleep to truly transport themself between dimensions

JynX said that there are "no longer" alternate Yabusames across different dimensions, the Yabusame we see always being the singular Yabusame (Which raises very curious questions about BPohC, actually)

A popular theory as to why this is, is that Yabusame exists simultaneously as one being throughout all the dimensions.

It would seemingly explain why they are so very scatterbrained, as their attention is literally scattered across various dimensions; as well as why killing them would be a permanent action even if time was rewound, as time is a dimension itself.

If this were the case, then perhaps sleeping to travel between dimensions is merely for Yabusame to shift their main focus between them; and the fact that there are "no longer" distinct, separate Yabusames in each dimension would imply a fusion/takeover of some sort.

However, we should of course keep in mind that this is all a theory, and is nowhere near confirmed.

String Theory

Disclaimer: Physics is not my strong suit, and I know next to nothing about string theory, so while this is probably the juicy part I won't be able to say much here. All I can do is point out some neat little references.

Yabusame's birthday, 26 November (26/11) may be a reference to the dimensions required in different variations of string theory: The M-theory calls for 11; while the Bosonic string theory calls for 26.

The M-theory is also referenced in Yabusame's personal themes Wings that Transcend Spacetime ~ M theory and Feathers Flying off the Beaten Path ~ Eleven-dimensional.

EmEv Holdover: Serintsu

So I sort of, kinda lied when I said that we can't identify any basis for Yabusame. We do have one from Emergency Everyday, the dropped predecessor of Len'en from which our modern Len'en is based on. We should keep in mind, however, that JynX did not work on EmEv.

It is likely that Yabusame is somewhat of a renewed Serintsu.

A human with the ability of "something like crossing dimensions", from what we can see of EmEv's trial version, their story from their game is largely identical to that of Yabusame's in EE.

However, other than this, the two share no other similarities and it is fairly safe to say that EmEv's main influence on Len'en comes from its premise and story more than anything.

So! I think that concludes our little look at Yabusame. Truly a mysterious but extremely fun character, let's hope we get to learn more in the future~! Until then, I leave you with this early concept art of Yabusame, which I think deserves to be appreciated more! :)