As long as Oda wants, cause Luffy fights are ridiculous sometimes. Most can last 15-20 chapters while everyone else hasn't even started fights yet.
Key examples:
- Luffy vs. Lucci: Started after Franky and Chopper had their fights and the middle of Nami's in like Chapter 405, but before even Zoro and Sanji got their 1v1s. Then it lasted another 12 full chapters after lmao. Basically 23-25 chapters altogether
- Luffy vs. Doffy: technically starts in 759 while everyone is mostly matched up, but then basically gets pushed aside for a Flashback, 2 chapters with Bellamy, then everyone's 1v1's. Then it resumes properly at 780-790, with some stuff in the middle obviously. So a good 10-11 chapters of mostly fight content in that ~30 or so chapter span.
- Luffy vs. Kata: basically starts in 877 with virtually no breaks (except when Luffy runs for 2 chapters) until 895. So basically 18 chapters of fighting while other things happen.
- Luffy vs. Kaido: The most egregious example. Starts in 1000 with everyone, then becomes a 1v1 in 1010 and only lasts 2 chapters. Then he comes back in 1026 after everyone has their fights sans Sanji and Zoro.
From 1026-1042 (17 chapters), he's basically fighting Kaido until he loses due to CP0. Then 1044-1049 is the rest of the fight.
Essentially, post TS major enemies all take between ~20-25 chapters on average to lose once Luffy starts fighting "without" major interruptions (this is while everyone else is fighting). The exception is Kaido since its more like 50 chapters, but Luffy lost twice, and then resumed at different points.
Essentially I expect either:
- Luffy vs Kizaru to last ~20-25 chapters nonstop while others are fighting to in the middle
- Luffy vs. Kizaru to get interrupted for x amount of chapters and resume later, basically the same span of 20-25 chapters.
Tldr: Egghead probably has about 30 chapters left its like.....a staple with Luffy fights.