9:20 That scene was from Ple Ple Pleiades, An OVA series with 3 seasons I think, Focusing more on Nazarick and Pleiades battle maids. It's Non-Canon, But worth a watch if you really enjoy overlord and wants to explore Nazarick a bit more. I wish they had Aureole Omega appear in it though.

20:10 her creator gave her bunch of skin based on his kinks XD

There is just so much mystery in floor 8, but we will never learn about them. but yeah next video already sounds good, can`t wait to see you learn about the special 5.

9:20 that was ple ple Pleiades it's extra/ OVA content based around the six sisters while it's technically not canon It does flush out their character and dynamic more. It's definitely worse to watch. It's like 2 hours in total worth of content . the anime you were thinking about was isekai quartet where 4 of the most popular isekai were put into a school setting Those isekai being Overlord, konosuba, re zero , and tanya the saga of evil.

unrelated but another trailer for the Overlord movie was released. Would be great to see your reaction vid for it.

so far in light novel no appearance yet, maybe last novels or side story only

Albedo's secret elite attack unit that she tricked Ainz kzfaq.info/get/bejne/h9Bghqx23tvTip8.html

17:00 This is sort of inaccurate, Maruyama (author) has confirmed typically a level difference of 10 is impossible. And it was level 80 not 75 that have to accompany Floor guardians. Basically, a level 90 normally can not win against 100 without some kind of advantage to even have a chance. 100 to 100: 50-50 100 to 99: 52-48 100 to 98: 54-46 100 to 95: 60-40 100 to 91: 90-10 100 to 90: 100% chance of victory

Is that Holo or Raphtalia?