From Season 2 Episode 2.
In order of appearances, the prisoners are:
1. (Presumably) An unnamed Giant (possibly the 'Dung Beetle' Giant).
2. Porphyrion (the leader of the Giants).
3. Prometheus (Titan, who gave humanity fire).
| OR |
3. Tityos (Giant, son of Zeus, who tried to rape Leto, mother of Artemis and Apollo).
4. Sisyphus (former king (of (Ancient) Corinth/Ephyra), who tried to cheat death by capturing the God of Death, Thanatos).
(Thanatos was sent after him either because Sisyphus killed his guests, or because he witnessed one of Zeus' many philandering activities. Either way, Sisyphus escaped Thanatos/Hades twice, resulting in his boulder-rolling activities.)
5. Tantalus (son of Zeus, who served his son to the Olympians, as a meal).
6. Seraphim (Demon).
About Prometheus/Tityos:
The prisoner shown in 0:08 could either be Prometheus (German / Brazilian Portuguese credits), or Tityos (Italian/Spanish credits). Both suffered comparable, similar, punishments.
Interestingly enough, according to the (German dub) credits, Atlas made an appearance in the episode, too.
I didn't manage to find him, though. I have some guesses, but I am not too confident in them.
Sebastian König is credited to be both Prometheus' and Atlas' voice actor.
![](https://i.ytimg.com/vi/ub6zaFI9V6A/mqdefault.jpg)