Ryu and his party can come across Spar very early in the game by visiting the circus tent, but they're not important to the plot until much later in the game when the group requires their assistance to communicate with the dying forests. The Circus Director, having been possessed by a Demon, threatens to have monsters kill Spar to gain some fame for the circus. The party intervenes and defeats the director, only to realize the Spar has been a willing captive the whole time, waiting for people who know something is wrong in the world. Spar joins the team and aids them by communicating with the great trees throughout the world. They are also pivotal in partially restoring the mind of the Wise Tree by helping Ryu and the party enter his mind and defeat the demon inside.
Spar is very knowledgeable, but their personality is rather cool and inexpressive. They displays very little emotion, even when faced with the prospect of being killed by monsters at the circus. Spar's primary drive for fighting with Ryu is their duty to protect nature from the negative impact of the demons. Spar's field ability is "Forest Walk." With Spar in the lead, they can walk through forest areas that are otherwise inaccessible to the rest of the party.
Spar is an overall weak character in battle. They utilize whips, but their attack power is lacking and does not acquire many useful damaging spells, limited to single target ice magic. Spar's strength lies in the plethora of buff and debuff spells they receive, making them an ideal support character and secondary healer. Spar's battle ability is "Nature," which depending on the geography will produce different results, such as exploding cacti, trees literally attacking, healing, etc. This ability is useless in areas without nature (i.e. dungeons such as towers or underground areas).
Spar has the most Shaman combinations available and the most possible transformations. They can become a small flowerbud, a child-like witch character (modeled after magical witch girls in anime) or a snapdragon (a literal take on the actual plant bearing resemblance to its mythological namesake). This large number of forms can help boost their lower combat ability. Their Flowerbud form in particular makes them physically stronger and more durable. The Witch Girl form greatly enhances their magical skills and the Snapdragon form makes them a much quicker fighter with a somewhat higher critical hit rate.