WARNING: The following contains spoilers for Blade Runner: Black Lotus, Episodes 10, 11 and 12 "Clair de Lune," "All the Best Memories" and "Artificial Souls," airing on Adult Swim and now streaming on Crunchyroll.
Niander Wallace Jr. (Jared Leto) is the villainous CEO of the Wallace Corporation in the Blade Runner 2049 film starring Ryan Gosling. Having taken over the replicant industry from Tyrell Corporation, Wallace Jr. is a ruthless businessman who is obsessed with creating completely flawless and obedient replicants. In the original film, he uses and disposes of replicants as he sees fit and as clients are willing to pay. In many ways, Blade Runner: Black Lotus is his origin story.
Throughout Black Lotus, Wallace Jr. took a back seat to his father, Niander Wallace Sr., and waited patiently for the tide to turn in his favor. In the lead-up to the penultimate episode, not only was Wallace Jr. revealed to be Elle's former lover who tattooed the black lotus on her back, he was also revealed to be her creator. More horrific yet is the reason she was created in the first place: to assassinate his father so Wallace Jr. could gain control of Wallace Corporation.
The way Wallace Jr. played his cards throughout Black Lotus has been pretty insidious, but Episode 11 made it clear he's been manipulating Elle from the start. It started with him taking advantage of his father's Doll Hunt to get Elle into a position of seeking revenge. He then sat back as Elle murdered all the people who participated in the Doll Hunt, until she finally got to his father. Once Elle fulfilled her purpose, Wallace Jr. had no further use for her and activated a new replicant, Water Lily, to retire her. The insidiousness doesn't end there, either.
Wallace Jr. had also hired Joseph, a former blade runner, to gain Elle's trust and guide her into fulfilling her purpose. Fortunately for Elle, however, Joseph has the one thing Wallace Jr. lacks -- a heart. As Episode 10 of Black Lotus revealed, Joseph was a lot like Blade Runner's original protagonist, Rick Deckard (Harrison Ford).
Like Deckard, Joseph was a blade runner who met and fell in love with a beautiful female replicant who sang at a nightclub he frequented. He was originally hired to retire her, but ended up sparing her life. It was actually his former associate and fellow blade runner, Marlowe, who ended up retiring her. This marked the end of Joseph's blade runner career.
In the present, Joseph ends up betraying Wallace Jr. to protect Elle, having grown fond of her. Instead of retiring her as he was originally hired to do once she fulfilled her role, Joseph tries to persuade Elle to have her memories erased and to restart her life somewhere else.
To ensure Wallace doesn't send another blade runner to retire Elle, Joseph lures Marlowe to his place and engages him in a deadly fight to the death. Though Joseph barely escapes with his life, he succeeds in killing Marlowe with his own weapon. In many ways, this act was about seeking justice for the replicant he brutally murdered years earlier and protecting Elle's future.
Since Elle doesn't end up getting her memories erased thanks to the deadly intervention of Water Lily, she sets her eyes on killing Wallace Jr. with Joseph, now that she knows the truth about her own origins. However, since Blade Runner fans already know Wallace Jr. will survive this encounter, Black Lotus can really only end one of two ways: either both Elle and Joseph die trying, or they both fake their deaths and restart their lives somewhere else like one of the alternate endings of 1982's Blade Runner.