Medea: She is the face of an NP-spamfest team. Lv. 4 of her 1st skill gives you an instant NP, her 3rd skill removes an ally's debuff and increases their NP gain rate and even her NP itself provides her with NP gauge, making her NP very much spammable.
Serenity: Unlike Medea, her NP isn't spammable due to her low NP gain rate. However, she still is useful as an NPer for her incredibly deadly NP. Her NP combined with her post-interlude 2nd skill and her 3rd skill leaves the enemy dead whether the the instant death works or not.
Hans: (He was mentioned in the article btw) He's often referred to as the mini-Waver for his team buffs and crit stars, the healing in his NP may seem low but is actually very helpful even or especially in the late game. He gives critstars through his 3rd skill and strengthens them using his 1st skill. His NP gives buffs and healing and is very spammable thanks to his 2nd skill
Mozart: Though he doesn't provide healing unlike Hans, he provides great debuffs to the whole enemy team throufh his NP. His 1st skill also a Arts boost for the whole team which is damn usefule for an Arts team.
Asterios: He isn't the most ideal support for an Arts team considering he has only 1 Arts card, meaming you can't Arts Brave Chain even with his NP. However his kit provides decent buffs for the team and his NP gives good debuff for the enemy team.