Arlecchino has been mentioned in multiple voice lines, and she finally made her first appearance during the "A Winter Night's Lazzo" trailer that also revealed all the remaining Harbingers.

Source: https://gamerant.com/genshin-impact-arlecchino-weapon-type/

Arlecchino may have the ability to control HP, while Charlotte is expected to be a Cryo healer similar to Baizhu.

Source: https://gamerant.com/genshin-impact-leak-arlecchino-cloud-retainer-charlotte-details/

The future banners in Genshin Impact allegedly include anticipated characters like Navia, Madame Ping, and Arlecchino, which excites fans and offers potential game-changers.

Source: https://gamerant.com/genshin-impacts-future-patches-banner-leaks-characters-available-when/

The official storyline confirmed that Arlecchino, also known as "The Knave" runs the famous House of the Heart orphanage that raised a lot of notable Fatui warriors.

Source: https://gamerant.com/genshin-impact-fan-arlecchino-columbina-character-portraits/

While Arlecchino is initially portrayed as a main villain, players expect her to eventually join the playable roster and have the ability to control different types of elemental lifeforms.

Source: https://gamerant.com/genshin-impact-arlecchino-harbinger-rank/

While many players hoped that she could be a sword user, recent rumors claim that Arlecchino will be a polearm character.

Source: https://gamerant.com/genshin-impact-leak-arlecchino-in-game-model/