"Gusoku Musha" is an original work by Wanderer-P, featuring KAITO and Gackpo. The song was initially published with 2 versions, both KAITO and Gakupo's, uploaded between 10 minutes; and a week later was followed by a duet version between the two. It is a rock song, talking about the insignificance of pride and the need to always push forward, never looking back.
In 2016, a remastered and an English version of the song were published for KAITO's 10th birthday. For the english version, the lyrics were provided by Korowan.
If the impregnable walls of question
may stand in his way from now on,
he blindly throws himself headlong into them
without a thought for how he looks.
Someone says the answer is impossible to answer,
or the best thing to do is run away.
Hack off such thinking like a good loser
with the blade forced by the past with sorrows!
Don't hesitate to go ahead!
So that he may not repent,
he stares straight ahead without looking back.
Recklessness is no reason to come to a standstill.
He reveals his weakness he knows only too well.
Rush ahead, absolutely perfect fool!
He doesn't intend to live wisely,
because if he burns out his life someday,
the worth that he has done his level best
is hard to change into something else.
Someone says he won't lose unless he fights.
Such wishful thinking like an opportunist,
break it into smithereens
with his fist in which he clenches his will.
Be unafraid of death!
What breaks into pieces
is a stupid pride binding himself.
If he thinks only that it ends without dying,
all he can do is that he lives deadly.
Keep challenging, unrivalled simpleton!
His life is full of wounds.
If he is knocked down
he rises many times and goes on ahead.
Without glancing at the onlookers with ridicule,
he turns a bad name into a decoration.
Try to be the strongest fool in the world!