A breed that prefers peace to drama
Russian Blues usually get along with other cats because their instinct is avoidance rather than confrontation. A Russian Blue meeting a housemate she dislikes will typically withdraw, choose a different room, and adjust her schedule, rather than start fights. That makes for peaceful multi-cat homes, with one caveat: a cat who always yields can also be the cat who quietly loses access to food, litter trays, and favourite spots. Good with other cats, in this breed, means the household has to notice the quiet dynamics and make sure peace is not being bought by one cat's retreat.
Pairings that tend to work best
The easiest match is another cat of similar age and tempo — a fellow adult who plays in bursts and rests a lot, whether that is another Russian Blue or any calm breed or moggy. Kittens are a mixed blessing: a Russian Blue adult often mothers or tutors a kitten patiently, but an elderly cat can find a kitten's relentless pouncing genuinely stressful. Two adult males, or a newcomer with a history of bullying, ask more of her tolerance. Wherever possible, choose on individual temperament and known history with other cats rather than breed label, because a sociable individual of a supposedly aloof type will integrate better than a nervous individual of a supposedly friendly one.
Introducing a second cat the slow way
Set the newcomer up in one room with her own tray, bowls, scratcher, and bed, and let the two cats learn each other's scent under the door and through swapped bedding for several days. Feed both near the door so company starts to predict good things. Progress to sight through a gate, then to short shared sessions with an easy exit for both, watching for relaxed curiosity rather than staring, flattened ears, or one cat blocking doorways. Litter trays follow the simple rule of one per cat plus a spare, placed in different areas, so the resident Russian Blue never has to negotiate for a basic need. Most pairs are sharing space calmly within a few weeks when nobody forces the pace.
Signs the arrangement needs adjusting
True fighting is rare with this breed; the warning signs are subtler. A Russian Blue who starts eating in the middle of the night, avoids a whole floor, over-grooms, or begins toileting outside the tray is telling you the social arrangement costs her more than it should. Respond by adding resources and vertical territory, feeding separately, and giving her a room that is reliably hers. If one cat is persistently ambushing the other at doorways or trays, separate and restart introductions at the scent stage, and consider behaviour help if the pattern repeats.
Knowing the newcomer before she arrives
A lot of multi-cat success is decided before the cats meet, by how much you truly know about the newcomer: whether she lived peacefully with cats before, what she eats, and which routines settle her.
KinsLe Transferrable Profiles transfer a newly adopted cat's profile to you with her history, records, and routines intact, so your Russian Blue's new housemate arrives as a known quantity rather than a stranger you are guessing about.