Best answer: No. Black Desert Mobile is completely separate from Black Desert Online, so nothing between your accounts will carry over or transfer from one game to the other.
Why doesn't Black Desert Mobile support cross-play?
Understandably, players would expect cross-play or some other crossovers between Black Desert Online and Black Desert Mobile. Both games are developed and published by Pearl Abyss, with the mobile version being one of the best Android Games available for anyone who loves massively multiplayer online role-playing games (MMORPGs).
Unfortunately, despite offering a similar experience, there's simply no cross-play or any cross-progression. There isn't even a bonus for playing both games. Despite the similarities, they are distinct games that receive updates differently and are balanced differently. In general, trying to sync the two up for even basic cross-progression would be a headache. Actual cross-play would be even worse. So, if you and your friends are looking for a new game to sink hours into together, you can play Black Desert Online or Black Desert Mobile. Just make sure you're playing the same game, or you won't be able to play together.
It's worth noting that the game's console versions, referring to solely as Black Desert, do in fact support cross-play. So, if you want to play on your PS5 while someone else is on the Xbox Series X, that isn't a problem. Unfortunately, while very similar to the console version, the PC version does not currently support cross-play with consoles. That said, we wouldn't rule out the possibility of this feature arriving sometime in the future.
What are other differences in Black Desert Mobile?
Both Black Desert Online and Black Desert Mobile take place in a similar land, featuring strife between the Republic of Calpheon and the Kingdom of Valencia. There are also many characters in Black Desert Online that are also in Black Desert Mobile.
The differences are mainly mechanical, not aesthetic in nature. While Black Desert Mobile looks great and has a high specification requirement, recommended 3GB of RAM on Android devices to run well, it's still a cut-down version. As such, the areas players explore tend to be more linear, focusing less on exploration and more on quickly getting into a fight.
It's still fairly complicated for a mobile game, though, which shouldn't be too much of a surprise. Reports indicate more complex mobile games are finding more of a market, especially in the U.S. right now. The fact that it's free-to-play, meaning the barrier of entry is incredibly low, only adds to the game's appeal.