Like I said that has not been my experience at all in my 30 years of gaming. I have never seen people fight to keep their characters alive in a high death game. The characters are disposable and that is how they are treated. We all had back up characters ready to go but none of them had backgrounds most of the table could not remember their character names much less anyone else character name.
We did not play as well as a team because since there were constantly new characters that we had not formed attachments to so we would not go out of our way to save them.
I've seen such games too. Even ''oh Elrod V died again, ok I'll bring in Elrod VI.'' But in my game the 'death aspect' forces all the players to work together. If they don't, they know they are dead....if they do, they will at least have a chance.
I think you missed my question. I am not saying having back up characters ready I was asking how you introduce them to the party do they just show up, do they have ties to the party already. Story wise how do you fit them in a way that makes the story make sense?
Well, new characters don't just drop out of the sky(well, that did happen at least once when a gnome's cloud clipper exploded and he fell on top of the fighter when his bummer chute failed to open until after he hit the ground....) For my two 'core' games, everyone has characters all ready made with backstories. Most of the time the story is kept vague such as it will say ''the city of _____'' or such. That way it can be fun padded in as needed.
It's easy enough to add in a character with the simple 'they are doing the same thing that the group is, just alone'' type plot. Another classic is just the tag along, where the character just joins the group as a pest. Otherwise a character can be worked into any story in seconds...in wonderful soap opera style (''Yes, I am lord Gunna's half brother...that no one talks about'').
In general, I don't do the sorts of back grounds where every single point of a character's history is interestedly tied into the world and it takes up a novella of space. I'm more then fine with ''Dogu is a fighter from Crossguard and has done nothing yet in his life''. And I really hate closed minded, closed plot type backgrounds like ''my parents were killed by orcs so now I hate and kill all orcs(and do nothing else)."
I am not the only one who seems to think that you are saying there are safe games and killer games several other people have pointed out to you that there is a middle ground
Where do you see a middle ground between 'character death at any time' and 'maybe character death at the right time if the plot and story call for it'. For example, my players are careful of every trap...they know that all the traps might kill a character. But in other games, the other DM would never, ever kill off a character with 'just a trap'. So the players know everything will be fine. The players know that the safe DM has planned a great story, plot or boss fight so the characters 'automatically' have to be there and alive for it to happen. A safe DM would never kill off a character just three minutes before a 'big event' and have that poor player 'unfairly' miss out on all the fun.
That is simply not true in my game. My players invest in their characters to the point that they actually take time out of their busy lives to write game journals, they search for the perfect miniature. When death has happened you can tell that the player who lost the character is upset and so is the party. Not angry upset but genuinely feeling a loss. That death had meaning to the entire table. Which is why I don't take death off the table but make it rare.
My players do this too, but they have to go all out to keep that favorite character alive and well. And the favorite character has a big negative in a lot of safe games....they Can't die. Player Billy (and the DM) like Rog so much that the character will never ever die. Even if Rog 'should die' he will, amazingly, survive (Billy-"I rolled a 1." DM-"Oh, um, er, you fall towards the endless pit of doom....but, but just before you fall in the winds shift and you land on a tiny spur of rock just outside the pit!")
My party works together as a team to make sure no one dies and they make smart plans and use good tactics. They are never blase about combat and you can see them get tense and worried when the combat looks like it is going against them.
But as your not a killer DM type, your group knows that things won't get too bad.