Marci is a unique character that's coming to Dota 2 not so long after the time of writing but the fans have already seen her in a different setting.
Valve announced the next Dota 2 hero that will join the roster during autumn of 2021. That leaves us with just over two months of a release window since the season ends on December 21, 2021.
Marci is a unique hero in that she is mute - we could see as much in Dota: Dragon's Blood where she appeared for the first time. She is a rather friendly character who serves as a bodyguard to Mirana in the TV show. The duo meets Davion, each on their own quests and while they eventually end up as allies, that's not all there is to the character.
While she is a sweet and friendly character, Marci is not a princess' bodyguard for no reason. She possesses unmatched strength and is not afraid to get her hands bloody. You can see as much in the anime or even the show's highlight reels.
Alternatively, you can just check the trailer below until the end - it will give you a rough idea of what the girl can do to foes several times larger and heavier than her. It would be reasonable to assume she will be some type of brawler when she arrives to Dota 2, with punches that would make the game's resident powerhouses proud.
There is also the matter of her voice lines, since Marci is mute. It remains to be seen whether Valve will keep her completely silent or do something similar to Riot Games with Sona in League of Legends, where you can hear the character's thoughts while using abilities, moving, attacking and so on.