Ok, so here is my idea for [Fembaru's Delusions]
Sort of Omake-ish timeline for what happened to Darkbaru as far as she can assume.
Arc 1
Loop 1: He was stranded in the Royal Capital of Lugunica just like her, with almost nothing to his name. He wandered around and ran into the thugs. Emilia saves him. He helps her reach the loot house. Elsa kills him.
Loops 2 - xx: He figures out how to fight against her without involving anyone else, because he is just based like that. Even learning weak fire magic somehow to counter her specifically. He still gets wounded and Emilia takes him home. He does get fame and reputation because he did things on his own without help (according to rumors which don't even mention Puck or Emilia).
Arc 2
Loop 1: He wakes up in the mansion and goes through the same routine as her. Flirting around and chilling. Then he dies from Meili's curse like she did.
Loop 2: He wakes up and tries to investigate what happened. Eventually is killed again by Meili or Rem for being suspicious. Figures out that he is being attacked though and thinks he needs to get strong and train. He will from now ask to be Emilia's guardian instead of a servant.
Loops 3 - xx: He asks Roswaal to teach him magic and eventually gets Beako to form a contract with him as her special person too. Together they go and bust Meili, averting the wolgarm attack completely. He also successfully dodges Rem's wrath by helping her get over her trauma and self hatred with... lewd romance?! Oh well, she can't judge since she would have too, but she was too much of a coward to return Rem's feelings back then after being killed by her.
Interlude arc/ (Where Fembaru just spent 2 months doing nothing important at the mansion)
He keeps training magic with Ros and learning lore with Beako. He also gets Meili and Emilia-tan to open up to him by not being as cringy as her probably. He now knows that Meili works with Elsa and that they work for Capella and is even more determined to get strong, to protect Emilia-tan's smile!
Reinhard shows up to join the Emilia camp on his own. Since Reinhard didn't find the 5th missing candidate, they presented some random new girl called Melty as one. Rein however did not accept her and left to join the Emilia camp. "It was that easy to get him?!" - Fembaru yells pulling her hair in frustration. Anyway, Darkbaru asks Rein to train him to be strong with the sword, because now he is Ultra Motivated to get stronger and is not messing around.
Rein spars with him repeatedly and Darkbaru keeps looping and trying again and again until he hits a limit on what Rein can teach him even with his divine blessings made for teaching. Keeps also training magic with Roswaal in order to combine it with what Rein is teaching him, for their ultimate final battle. This is their famous battle that culminated in the "Rainbow Sky" (Fembaru wipes her drool, the filthy fujoshi degenerate). Where they fought to a "standstill" as far as everyone is aware - though obviously Rein was holding back. Still impressive as hell.
After this Darkbaru feels confident enough to finally act on doing something about the tower of Pleiades and the Sanctuary, which he studied on from using the knowledge in the Forbidden Library (that burned down because of Fembaru being a baka in her timeline, leading to more self loathing on her part).
Roswaal is also happy with how things are developing, since he clearly doesn't need to mentally break this version of Subaru in order to get him to start looping like crazy. This is why Roswaal likes him so much, to the point where it's creepy even.
Tower of Pleiades - Arc 2.5
Loop 1: He goes alone and because he is just built different (and because of Beako and the forbidden library) he breaks through the Sand Time barrier. He gets killed by Shaula though.
Loops 2 - xx: He figures out how to counter Shaula's lazer beams by inventing a specific Yin spell which he calls "Limitless" ("Damn that's such a chuuni name... I love it so much!!!" - Fembaru). He then proceeds to attempt to conquer the tower after Shaula accepts him as the return of her master from 400 years ago.
Loops xx - yy: He fails to conquer the tower, dying and suffering to try again (suicide), but never giving up. He successfully resists getting his memory erased unlike her and going crazy, since he do be built different. He learns more things about 400 years ago though and probably meets Satella in person. This is the one time she mentioned him coming to her Shadow Garden to "visit" her, since Satella probably wasn't talking about him simply not dying multiple times as far as Fembaru thinks, since that would be crazy to her, anathema even.
Eventually Darkbaru must have simply realized though that completing the tower right now meant giving up Shaula... and he chose her and decided to take her home. Saving yet another person that Fembaru has failed in her timeline.
Sanctuary - Arc 2.6
Loops 1 - xx: Now being even more mentally prepared to handle the Witches of Sin, Darkbaru goes to the Sanctuary. He doesn't involve Emilia, because he figured out how to convince Puck to return her memories and forge a new contract, by virtue of having more rizz and that DAWG in him - that is suiciding multiple times while figuring out how to say the right thing to support Emilia-tan and get Puck on board. This means that Emilia no longer needs to pointless suffer and get tortured by Echidna... like Fembaru basically forced on to her... (more self hatred and [Envy]... as well as admiration and love for Darkbaru).
In the Sanctuary he confronts Echidna and forces her into a much better contract than Fembaru could have ever considered, where he holds all of the cards over Echidna, by leveraging RBD in a way she was never mentally prepared to. There he also supposedly passes the trials... and gets white hair from stress of doing so... Because his second trial likely was INFINITELY worse than hers, horrifying to a degree that Fembaru could not even begin to comprehend herself...
There he also breaks the barrier and recruits Garfiel. With Darkbaru acting as a mentor and role model figure, instead of a pathetic excuse for a 'captn' that she was... With him actually being someone worthy as a leader, rather than someone pitiful... unlike her... [Envy[Love[Envy[Love[Envy[Love]...)
Arc 3 - but the 'Prophecy of the Throne' Electric Boogaloo version
Fembaru is looping to save Priscilla from the Witch Cult/Assassins that keep popping up. They are clearly showing up in this timeline due to the butterfly effects of things like Melty being a candidate and Reinhard being away from the capital, or any other combination. But she is desperate and she can't hold on like this for much longer! Not with Satella spitting hatred at her every time she dies! She is about to break for the last time... Won't someone save her...?!
Then her fairy tale knight in shining armor arrives. The one she hates. The one she envies. The one she loves.
Just as she is on the edge of the abyss... he holds out his hand to her and says, "I've got you now cutie. It's going to be alright, all the suffering is about to end."
(Meaning that he finally found his [Cocksleeve] and will no longer have to suffer the agony of not being able to fuck himself)
He is so much more good looking than her, so much more heroic and cool, his voice like honey, his eyes so deep she can drown in them and so far away and thoughtful (the plans for making a loli layer cake won't come up with themselves) and yet behind the smile he is wearing he is hiding a mental burden so heavy that her own can't even compare, if his hair white from stress and the dark bags under his eyes are anything to go by... (he spent the entire previous night having an orgy with his harem and didn't get any sleep)
[To be continued?]
Anyway, this is just an idea of how I can imagine it would go. It can go in a completely different direction and I could enjoy it much more than anything I could come up with myself, but this version of how Fembaru will interpret Darkbaru's actions was just stuck in my head for a while and needed to be shared.
I'd love if this is how it happens actually, sure, but Fakeking can just as easily make me enjoy a completely different take just as much if not more.