Characters who started in the Eternal realm at the launch of Diablo 4 were not supposed to be able to move to the new Seasonal realm. However, a newly discovered glitch broke down the barrier between the two by disconnecting the Internet connection.

Seasonal characters in Diablo 4 inherit some of their progress from Eternal Realm characters, but start at level 1 with no items or gold. Seasonal is essentially an opportunity to resume the trek to level 100 with the help of unique mechanics.

Apparently the two realms are not as separated, at least on a technical level, as Blizzard would have you believe. Players have discovered that if they group with a friend in Seasonal Realm and then temporarily disconnect from the Internet, they can log back in as an Eternal Realm character with all of that friend's stuff.

YouTuber Glitch Unlimited explains this forbidden realm-hopping technique and gives several examples of how it benefits characters on either side. Eternal realm characters can sell items and get gold to spend in the Seasonal realm. They can also obtain and use seasonal Legendary items. Malignant Hearts, however, cannot be used outside the Seasonal Realm.

Eternal characters can also leave powerful items for Seasonal characters. In other words, if you are unlucky, you can give powerful Legendary or Unique items to your Seasonal character.

Given the strict rules for items being transferred between both realms in "Diablo 4," this glitch will not last long until Blizzard fixes it. If this glitch is not an obvious violation of the rules, such as a server misunderstanding where a character should be placed, then it would be better to take advantage of it now. However, it is very likely that Blizzard will punish anyone who uses it, so I personally would stay away from it.

There are enough changes in patch 1.1.1 that the items you inherit may only be available for a week or so. Full patch notes will be available tomorrow and the patch will be released next week on August 8.