That's how Call on Friends works for other characters, too. It still generates teammates from the pool of available ones (+Fairy of Light when upgraded). So if you don't have Cirno's relic, the pool will be quite small, as most characters have only 1 teammate, and as an off-color.

In base game, this is most noticeable when you get Call on Friends through Breaking Boundaries.

I like Fervor, just because it rewards big attacks way better than Firepower.

But I used Garden of Borrowed Dreams to get Cirno's Unique "Call On Friends," and when I played it, it never let me pick a teammate card. It just went straight to discard with no effect. So I upgraded it, and when it's upgraded it always provides a Fairy of Light as the fourth option, and then it would only display the Fairy of Light and nothing else. I don't know what caused that bug, but figured you might want to know.

Thank you for your Chinese local translation

Now with Chinese localization, courtesy of 防护林.

Fervor might look boring, but unlike temporary firepower (which rarely gets to high numbers unless you're looping), it's very explosive and priced appropriately—mostly on expensive cards, often in delayed form. As such, it requires good timing to make best use of and makes for a flashy payoff when your attack suddenly does over a thousand damage.

It also goes well with other damage modifiers like Vulnerable due to its multiplicative nature (which base deck tries you to teach—defend with Radiant Glare, retaliate next turn).

I find Red Yuuka significantly harder to play than Green, because you need to plan ahead with how your bursty turns will be lined up, otherwise these big flashy effects will whiff.

Most of the mechanics are quite fun (I especially like the optional nature of Flourish and the increasing drain speed of higher levels of Bloom), but Fervor feels kind of dull by comparison – sure, it's mathematically different from Temporary Firepower (more advantage to bigger cards rather than to multi-hit ones), but it doesn't feel very different.

So far, no. If anyone wants to contribute, I am always open to adding more localizations.

NO Chinese?