#lrbbox

You ever get the vibe that the "old" Sectonia was fully gone once she was okay with hurting Taranza? I think for him, that person is his sister.

4 (Has your OC met Kirby? If they have, what is their relationship with him like?):

Nope! Tarantillda has never met him. She has been to Dream Land a time or two (long before the events of Triple Deluxe), but while she may have heard Kirby's name in passing, they've never actually happened upon one another.

12 (Is your OC open with their emotions, or do they tend to keep their feelings bottled up inside?):

For Tillda's introductory episode ("Flower Power"):

A young woman from another planet arrives in Dreamland seeking her brother, who apparently went missing some time ago. She looks through the whole town and doesn't find him—but, just when she's about to leave Pop Star, trouble appears: it's Flowery Woods, a tree-like demon beast! It begins to take over Dreamland and chokes out the sunlight so that Cappy Town is covered in darkness. Tillda, knowing some plant magic and hopeful that her brother might appear alongside Flowery Woods, sticks around to help.

After the fight, she explains that Dedede isn't the only monarch that has been lured by NME to the side of evil—her homeland, Floralia (which probably works better as another planet entirely in the anime-verse), was turned to a miserable place after their tyrannical queen swore loyalty to Nightmare. Tillda meant to grab her little brother and escape the place, but he was lured away and turned into a demon beast himself, leading Tillda to search planets for signs of Nightmare-sponsored trouble and, hopefully, bring her brother back to the light.

The episode ends with Kirby and friends waving her off, promising they'll keep an eye out for Taranza. (She and Tiff would probably take a shine to each other over the course of the episode, since they both play the role of sharp elder sister to an adventurous little brother in a world full of danger!)

For Zed's introductory episode ("Over the Rainbow"):

Kirby, Tiff, and Tuff are playing in town when they see an unfamiliar feline face pass by. Though the newcomer isn't very talkative, he seems friendly enough—especially to Kirby, who is excited to meet a new friend. Tiff and Tuff, on the other hand, are mildly suspicious, but agree that they should learn more before they interfere—especially after catching a glimpse of a strange, black, blob-like creature with one eye displayed on Zed's portable computer.

Later that day, a blight of Dark Matter (which no one in Dreamland is particularly familiar with) descends upon the townspeople. With the exception of Tiff and Tuff, everyone around Kirby starts turning angry and violent, including Lady Like and Sir Ebrum; when the three protagonists encounter several strange, one-eyed creatures, they remember Zed from earlier in the day and assume he is a demon beast summoned by Dedede to bring the blight upon the town.

Zed is discovered huddled away writing notes about the monster. Tiff and Tuff threaten to attack, but Meta Knight quickly swoops in with exposition. Soon everyone calms down and listens to what Zed has to say—that the darkness over Dreamland can be expelled if the leader of the occupying Dark Matter army, the Swordsman, is defeated.

In reply, Meta Knight mentions that the Star Warriors previously defeated Dark Matter Swordsman using the Rainbow Sword, which has since gone missing; Zed then reveals themself to be in possession of this legendary weapon and offers it to Meta Knight, thinking that this must be the hero that can defeat the Dark Matter Clan yet again—but Meta Knight, who already has Galaxia, insists Kirby take it so that the two can join forces to stop this very powerful threat.

Hence DMS is defeated by Kirby and Meta Knight, leaving its army to flee and Dreamland safe and peaceful once more (much to Dedede and Escargoon's relief—the Dark Matter ended up possessing them, too).

Zed exits without much of a goodbye, let alone an explanation of who they are, where they came from, or why they helped fight against the Dark Matter Clan. Meta Knight is left to ponder aloud that, like Fofa, maybe there are other demon beasts that turned to the good side, for one reason or another.

Afterward...

Q8: This one is easy enough to answer for all of my OCs; at a practical level, I wouldn’t consider any of them to be “the only one of their kind,” since none of them are/were the sole member of their species. (I would consider engineered/mutant characters like Elfilin, Queen Sectonia, and the Master Crown, for example, to fall into this "unicorn" category.)

Some of my OCs are unique in other ways. Zed is the only N-Z on the planet where they and Tillda live, for example.

Q10: Zed doesn't, really. Tillda holds grudges sometimes, but I would say they're mostly superficial. Of all my OCs, Miz-Baranez (the N-Z General) is probably the least forgiving, and Cardnyl (the Jamba priestess) is the most forgiving.

Q21: All of my OCs are adults, though their actual ages vary greatly. Nan-Zee and Zed are the youngest and the orange ball is the eldest.