Based on the data and the similarities, it seems likely that the fight with Rennala in Elden Ring may have stemmed from the content that was cut in Dark Souls 3.
While each game is different enough, FromSoftware is clearly referencing old ideas, evolving and re-improving them. This is sometimes most evident in boss battles. For example, the general design of the boss battles between Elden Ring and Bloodborne’s Malenia and Lady Maria is extremely similar. However, it looks like this could also happen with Rennala. New evidence has emerged that suggests the Elden Ring boss fight with Rennala is something FromSoftware may have cut out of Dark Souls 3 – specifically from Rosaria’s boss battle.
This was pointed out by FromSoftware-oriented YouTuber Zullie the Witch, who initially pointed out similarities in Rennala and Rosaria’s designs. For example, both focus on reincarnation (even if it goes wrong), both claim a position of nurturing their “child,” and their children are both “things” that can magic ability. Even so, each arena has cradles hanging from the ceiling, so it’s clear that their general design matches well.
What really proves this is the mined data that confirmed that Rosaria’s boss fight was cut from the game, though possibly cut before the game was in development. To support this is the way FromSoftware uses 5000-range character IDs specific to boss battles, and as Zullie pointed out, this keeps the Demon’s Souls chronological. The only two 5000 range NPCs without boss fights include Fire Witch, with Zullie claiming to have been replaced with Pontiff and Rosaria. Given their similarity in design, Rosaria’s character IDs, and other ratios, and endings in Dark Souls 3 and Elden Ring, it seems very likely that Rosaria will eventually become a combat style. Boss fights are revisited in Elden Ring with Rennala.
As noted above, Rosaria’s boss fight seems to have been cut early from Dark Souls 3, meaning there’s no strategy or approach to this boss. It looks like at least the first phase of Rennala will match Rosaria’s playstyle and that’s why FromSoftware will refer back to it. After all, this isn’t the first attempt the company has ever reviewed.
Another example of this is PvP-oriented boss fights. There’s a clear upgrade path from Demon’s Souls Old Monk’s fight to Dark Souls 2’s Look Glass Knight battle. That’s why something similar happened here, with FromSoftware repeating the game. Battle between boss Rosaria and Rennala. After all, while games like Elden Ring leave a lot behind, that content can always be revisited.
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