In Diablo 4, players choose between the Seasonal Realm or the Eternal Realm when starting a character in Season 8.The Seasonal Realm includes seasonal content, battle pass progression, and special mechanics for about 12 weeks.The Eternal Realm in Diablo 4 lacks seasonal features but receives new content, such as Uniques and Legendary Aspects, each season.Season 8 in Diablo 4 focuses on Belial and updates to the endgame boss system with new boss powers like the death beam from Wandering Death.It is recommended to play in the Seasonal Realm for the new character experience and to access season-specific rewards and progression.Eternal Realm players can still enjoy some new boss features from Season 8 but miss out on certain abilities and season-specific rewards.Players in Diablo 4 must choose between Seasonal or Eternal Realm characters and can only play with others in the same realm.Choosing the Eternal Realm may be preferable for playing with friends with existing characters or continuing progress on an old character.Players unhappy with seasonal mechanics or progress may opt for the Eternal Realm to avoid new content, depending on the season theme.Some reasons to choose the Eternal Realm include playing with old characters, finishing campaigns, or avoiding seasonal mechanics.