Speaking of Russian diminutives, would "Ilyushenka" be familial or romantic?
Very familial. -enk- is (typically, there are always exceptions) a very diminutive root, with connotations of being small/young. The way it was explained to me - let’s talk about our friend Ekaterina (Catherine).
She probably goes by Katya. Katya is your coworker, the girl you have a couple university classes with, maybe a barista you see regularly. It’s the equivalent of “Cathy” or “Katie”. (Ilyas generally just go by Ilya; it’s short enough that it’s already its own casual diminutive.)
Katyusha is your girlfriend or wife. It’s a little more intimate - you probably wouldn’t use it at the grocery store or in front of her parents. Kind of on par with “Cat” or “Kiki”, but more like calling her “baby” or “sweetcheeks”. (same with Ilyusha - the connotation is “my Ilya” or “my Katya”, because the -sh- makes it softer, but not smaller.)
Katyenka is your daughter or granddaughter. It’s like “Kitty” or “Kitten”. The connotation is “my little Katya” - if you say it in a sexy context, it’s probably gonna sound creepy unless you have one or two very specific fetishes.
If you look at it in terms of -ito/-ita suffixes in Spanish, Katya is one -ita, like calling your grandma Abuelita instead of Abuela because she’s your grandma. Katyenka (and Ilyushenka) is that thing Mama Elena does in Coco where she calls him Miguel-it-it-it-ito.
Ilyushenka is so diminutive that using it on Julian, since he’s an adult, borders on an insult 😂 Like, Mazelinka and Portia would only do it to make fun of him (“I don’t know what a Tik Tok is and at this point I’m afraid to ask” “Oh, Ilyushenka, so afraid of the scary video app”). Honestly, the only person who might unironically call him Ilyushenka at this point in his life is Tasya, because she tends to be very parental when she talks to Julian and Portia, like they’re still cute little kids toddling around her mansion.
If you want some romantic Russian pet names for Julian or Portia (masculine/feminine - copy/paste the Cyrillic into Google Translate for pronunciation):
Dorogoy / Dorogaya: [literally: dear] “my dear”, “darling”
дорогой / дорогая
Miliy / Milaya: [literally: nice] “sweetheart”, “darling”
милый / милая
Sladkiy / Sladkaya: [literally: sweet] “my sweet”, “sweetheart” (this one isn’t super common - it’s pretty gushy)
сладкий / сладкая
Solnyshko (neutral): [literally: a diminutive of “solntse”, sun] “my sunshine” - can also be platonic, for close friends!
солнышко
Kotik / Kotya (both masculine): [literally: little cat] “sweetie” or “cutie”, masculine
котик / котя
Rybka (feminine): [literally: little fish] “sweetie” or “cutie”, feminine
рыбка
Tigryonok / Lisichka: [literally: tiger cub / little fox] terms of endearment for a boyfriend/girlfriend with red hair
тигрёнок / лисичка
Krasotka (feminine): [literally: diminutive of “krasivaya”, beautiful] “gorgeous”, but it’s a little bit crude, kind of like “babe” or “hot stuff”
красотка
Sakharok (masculine): [literally: sugar cube] “sugar” (this one is super corny and also not very common, but Julian’s pretty corny, so)
сахарок
Umnitsa / Umnyashka: [literally: clever] “smart guy/girl”, usually used in a “that’s my boy/girl” context
умница / умняшка
Lapa, lapochka (neutral): [literally: paw, little paw] “cutie”, “honey”
лапа, лапочка
Rodnoy / Rodnaya: [literally: native, home, “own” as in “my own country”] “my dear”, used to denote a strong familial bond, although it’s almost never used for blood family; more accurately, it’s a soulmate, someone you plan to spend the rest of your life with, someone who is home to you
родной / родная
Lyubimiy / Lyubimaya: [literally: beloved, favorite] “my love” (can be casual, too)
любимый / любимая
Dusha moya (neutral) : [literally: my soul] soulmate, “my heart”
душа моя
Radost’ moya / Schast’e moyo (neutral): [literally: my joy / my happiness] “the love of my life”
радость моя / счастье моё
Masculine terms of endearment use “moy” before or after (dorogoy moy, moy kotik) and feminine use “moya” (rybka moya, moya lisichka), but it’s not a requirement if you’re mixing languages - it just means “my”.
(As always, I’m not saying the Devoraks are necessarily or exclusively Fantasy Russian; all in-game cultures are composites, and there are a lot of ways to interpret them. I just use Russian diminutives and language for them because that’s the language & culture I know best.) ☕