Clare is a young, naive girl currently living with Udonna in Rootcore, having been under the sorceress's adoptive care for around two decades. During her time training under Udonna, Clare has aimed to become a powerful sorceress of her own someday, just like her mentor. As a result, Clare works under Udonna, performing housekeeping tasks around the base, as well as learning new magic spells from her.
Unfortunately, though she apparently seems to have been training under Udonna for some time now, her spellcasting skills weren't initially as up to speed as her ability to follow Udonna's orders. She tried her hardest, but managed to screw up most, if not all, of the spells she casted. To date, she's cracked a crystal ball, dried up a lake, turned herself into a sheep and a goldfish, conjured up a swarm of bumble bees, turned herself totally bald, grew a beard, turned pieces of herself invisible instead of all of her, and even turned her hair to whip cream. One of her potions came dangerously close to turning Xander into a tree for good. It's worth note, however, that the antidote potion for that worked perfectly, unlike most of her potions and spells, and that her invisibility spell successfully worked one time out of three, proving that she does have skill hiding behind her mistakes.
It seemed like it will take forever for Clare to grow into her powers, and she's admitted her concerns to Udonna in the past. Udonna, however, would never give up on the girl, and assured her that she'll become a full-fledged sorceress one day. That assurance came true when Clare learned of the fate of her mother, Niella, and accessed her mother's powers to become the new Gatekeeper. With Clare's help, the Rangers were able to reseal the gate locking the Underworld, though Clare lost her lunar-based powers in the process. However, knowing that her own mother was bumbling much like her, and yet became a powerful sorceress of her own, has given Clare hope for the future that she can do the same, with or without the Gatekeeper powers. Her spellcasting ability has had a much better track record since then, seemingly as a result of newfound confidence in herself.
After the Gatekeeper incident, she continued her sorceress training at Rootcore. However, her role as of late had shifted more to taking care of Fire Heart, the dragon retrieved by the Rangers, who seems to believe Clare is its mother since she hatched the egg it came from.
Clare definitely knows the story of Udonna's lost husband and son, now that all the Rangers have learned about it. It's likely that she already knew of the story long before that however, even if she didn't realize Koragg and Nick were the husband and son in question.
More secure in her abilities as a potential sorceress, she decided to travel with Udonna to search for her once more missing husband. Unfortunately, the most recent appearance of Clare involved her being knocked unconscious by Hekatoid as he kidnapped Udonna. What will happen to the two of them now is up in the air.
Clare's exact age is unknown, since she wasn't shown, as an infant or older, in any flashbacks involving her mother. However, it's unlikely that she's too much older than her 19 year old cousin, Nick.