Lily, as The Heart (normally) has many sweet moments, from her protectiveness of Casey initially to her soft care of her best friend Theo and especially her love and care of master Phant.
In the final episode, Camille goes off to help the Rangers without Jarrod—because Lily once told her she was a good person, and Camille wants to prove her right.
Seeing Casey's journey from a whole series perspective is quite inspiring. He goes from an ostrisized and unsure "Cub", chosen at the last moment to replace a senior member, to a beloved member of the team, and eventually a respected master willing to help anyone with a second chance.
This also mirrors his actor's development too, who was initially unsure of his place in the franchise, had to work in the middle of a major TV strike, but managed to overcome and become not only a fan of the series (winning over fans of his own in the process), but one of more beloved actors to put on the red spandex.
Fran's development is just as great- starting out looking like she'd be blown over in a stiff wind, she, on her own, learns the Ranger's identities, covers for them throughout the season and saves RJ from his wolf spirit. Not bad for a support character.
A retroactive one. Near the end of the series, many characters say that Dai Shi's treatment of Camille normally is that of indifference and scorn, while Jarrod seemed to respect her far more as a minion. This could mean that any time "Dai Shi" stood up for her, protected her or wanted her to be more powerful was Jarrod the whole time. It seems even when being possessed, Jarrod was able to at least treat his minions with some respect, which considering his behavior before this, is definitely heartwarming.
Casey's whole battle to save Jarrod's soul at the end of the series is this, but particularly this:
Dai Shi: Jarrod no longer exists. I have swallowed his humanity, and he is now my slave.
Casey: No! You can't have him! He's Pai Zhua! He's one of us!
A big part of the series towards the end seems to focus on the theme of redemption. However, what's great about this series is that it's a Redemption Equals Life, so that by the end of the series BOTH of the main villains are on the side of the angels (well, "main villains" since Dai Shi got destroyed). Because it's never too late to start over.