Fandom noted and not confirmed by the show's creators. But with enough there to make us all wonder if it could actually be a thing.
Death Parade takes place in a strange outpost of the Afterlife.
Individuals dying at the exact same time may find themselves in bars, where they are forced to participate in games to determine their everlasting Fate. Arbiters doubling as bartenders judge the outcome.
In episode 11, Memento Mori, a character named Mayu is given the option of condemning a complete stranger to eternity in the Void. If she complies, then she may retrieve her lover Harada's soul, that he might regain it and they can continue on together.
But look at the stranger...
According to Ryuk - and indeed Death Note Rule 2.3 - no-one owning and using a Shinigami's notebook may continue on to Heaven or Hell upon their own demise. Instead the like of Light Yagami will end up in Mu (Nothingness).
Which sounds very much akin to Death Parade's Void, or even the bars themselves. Those hospitalities end up acting like reception rooms for those about to be lost to that infinite nothingness. It's a rare soul who manages to escape that eventuality, no matter how many games they play.
Not even Mayu and Harada really get away.
Official Reference Kira in Death Parade?
Madhouse was also behind the production of Death Note as an anime, adapted from the manga.
It's a company for which Nippon TV owns a 95% share. NTV recently utilized its own rights to the story and characters. It was behind the live-action Death Note (2015) television drama.
Actor In-Joke for Death Parade's Kira?
Look again more closely at what is being said at the time that the lookalike Light Yagami is shown in Death Parade. Harada may only live if Kira dies. So who do we (or, to be fair, Mayu) choose to survive this storyline?
It may illuminate or amuse you to note that Light and Harada are both voiced, in their respective anime, by Mamoru Miyano.
The voice actor would struggle to bring Harada audibly to life, if recording lines for Kira was a current pre-occupation of his career. One would imagine that he'd be pushed for time, taking on such a main role.
So yeah, Harada's unmuted anime soul really was quite dependent upon Light being lost to the Void.
Or a random stranger, whomever he might be.