Damn it all. I've reached the theorycrafting prompt and still have no idea why Oric wants Target dead.
Notably, I'm having difficulty with Al's Prison of Haria flashback. It's tempting to say that's the same "prison" Oric was mentioning, and it might be, but we know that Al's been here for three years and the Warrens have undergone thousands of Cycles. That seems to preclude the idea that Willford was talking about Oric & Crew specifically, though imprisoning heroes and then Warrens-dumping them could certainly be a time-honored tradition. I'm not sure how much to take as a clue and how much to be wary of as a herring.
Other things to note:
-Who was Oric talking and referring to during his infamous prison speech? We assume us and himself, but it was Riltia who got it. The "voice in the adjacent cell" thing could also mirror their particularly close relationship; maybe it was us that said "time to go" and Riltia whose only comfort was from our voice. It could be Riltia who's trying to "recreate the prison," rather than Oric.
-Riltia asked an interesting question we still haven't answered yet. "If I was working for Oric, why didn't I remember what he looked like?" Could be as simple as rebirth shenanigans, but it seems like a meaningful question we haven't formally answered yet.
-Oric was messing with us prior to the prison speech. This feels like pretty coherent proof that he's not
afraid of us, and that his wanting us dead is part of some ritual or process.
So... I guess my current working theory is:
Once upon a time, there was a Mad Tyrant of Haria
[1]. To secure his reign, he began imprisoning all those with the power to challenge him
[2]. Then he fed or exiled them to Hell, because he was a cool guy like that.
[3]Once in Hell, however, one of these condemned prisoners was offered a bargain. He took it, and transformed Hell into a self-sustaining turbine of soul feasting
[4]. Pleased that he had done all the thinking for Her
[5], the ruler of Hell decided to downsize
[4]. Being a thinking man
[5], the prisoner disagreed, murdered her entire race, claimed her servants as his own, and kept her around as a limbless lynchpin for Hell's continued operation
[4].
However... this prisoner had come from the prison of a mad, jealous king. He had usurped the throne of a decadent, arrogant queen. So he set about ruling his domain the only way he knew how: With the iron fist of an unimpeachable god
[6].
However, this prisoner was a thinking man
[5]. He knew the price of stagnation
[7] and he knew the fruits of motion
[8]. He knew that a tyrant must always have a usurper and a kingdom must always have a rebel
[9]. And so he arranged his kingdom such that this vital role would never be lacking
[10].
In short, Oric wants the Target dead because it's his job. It's The Way Things Work
TM, it gives everyone purpose and identity, it shapes and strengthens everyone via constant struggle, and it possibly ties in to the proper sustainable running of the Warrens as a whole. He probably literally doesn't know any other way.
[1] Al's mention of wanting to overthrow the king, the Oversoul being "a power sought out by evil rulers and corrupt dictators for millenaea," Ciro thinking he was from Haria originally, prison similarities
[2] Oric's description of being a prisoner, Willford's explanation of the prison and liking "tomorrow to be the same as today and yesterday"
[3] Oric's description of a voice saying "time to go," Oric's mention that "exile is escape, reward is punishment"
[4] Cain
[5] Al's speech about how dangerous a thinking man is, and how a man who doesn't think does strange things
[6] Oric's "recreate the prison" comment, Oric's overbearing relationship with Spira, Oric's concern with someone else finding an ultimate weapon, Oric's mention of needing to glare evilly at us now that we know who he is, possibly his peculiar obsession with us murdering Riltia or vice versa, possibly Cain's hatred although Cain is a murderous cannibal so he's probably not the best Freedom Index Test
[7] Cain's speech about Hell being unsustainable pre-Oric, Al's flashback about the contrast between Willford and Al
[8] Cain's speech about Oric fixing Hell (presumed), Cain's speech about Oric's struggles and triumphs, Ciro's flashback about Probably-Floe's speech about Ciro's strong will overtaking Floe, self-evident knowledge about the nature of adventurers
[9] Oric's tolerance of Ciro, Cain, Riltia, Ecco, Proxxy joining with Ciro, and so on; Cain's story about Oric's exile and rise to power
[10] Oric's tolerance of Ciro, Cain, Riltia, Ecco, Proxxy joining with Ciro, and so on; Proxxy's mention of only supposed to be fighting Ciro in her boss room, silhouette insinuations that Ciro facing defeat is a necessary part of a Cycle, existence of shopkeepers and shopkeeper areas on what are fairly literally random murder floors