Oh dear, this one almost makes me cry.
I got a cat for extra company (I had two already) and he was amazing to start with. He would really observe me. I named him 'Rabbit' (in a different language though). He and the two other sweeties got along so fine from the start.
In 2012 I took in a stray who was a sweetie. All guys got along perfectly, as usual, helping out in very stressful times. I would lie down with my face in the oldest cat's belly if things got very bad, it felt so safe.

The former stray had no idea what living inside meant and he was helped by Rabbit, who would also intervene if the stray 'growled' (complained) at me; he was just afraid and never lashed out, bit, or even scratched. He was a real sweetie, innocent, and very trusting since I could always pick him up, do his nails, no matter what. He turned out to be a Bengal, so those are more vocal anyway. Rabbit would come running if he heard him complain at me and would whoop his arse just to make a point. He really helped.
In 2013 a cat died, Rabbit did not leave his side until the day he died, just sitting close to him, being there in case he needed help. I have pictures.
In 2017 a second cat died, Rabbit again would watch over him, sitting close to guard him. He would not leave his side and one picture is so dear to me.
Rabbit stayed my super trooper and if I wanted to go out into the garden, for instance, and the former stray wanted to go out as well, Rabbit would grab him by his neck and drag him away from the garden door so I could step outside. Rabbit himself really wanted to go into the garden mind you, but he let me go outside while he held his friend.
Rabbit lost his last friend early 2021 during the pandemic; the former stray. He had serious heart problems and strokes. No vets could come to the house for euthanasia and he died 'a natural death' which was traumatic to me. Rabbit stayed with him for months, never leaving his side. I noticed how my cutie was getting sicker and sicker, having seizures, and Rabbit was there for him every step of the way. One evening he was so sad, I took him in my arms and we watched the garden together. I told him he would soon fall asleep and not wake up in this world, but in a different world in which he could be in the garden as much as he wanted, and that I would miss caressing him and playing with him, that I would miss his cute face, but he was too tired to continue like this and it was okay to leave.
Later that evening I went upstairs to brush my teeth. When I came downstairs, my sweetie had died. I had been with him every second, being in lockdown, and I missed his dying. Rabbit was lying next to him, not knowing what to do. I cried so much.
I cried until things got very quiet, and then I realised that all the love he had given me was still inside me. I could not end my life with the love Rabbit and the others have given me still inside me. It's very difficult at the moment since Rabbit is now very sick. I am pretty heartbroken. Tomorrow is animal hospital. Rabbit is now so, so skinny and light, it went so fast in spite of vet visits. I have no spare savings left so it would be wonderful if they find something that can easily be remedied but I also fear he is very depressed. I myself am still heartbroken.
Here is a picture of both Rabbit (on the right) and his last friend.