Bonfires aren’t just the places where you can save your progress. There are other functions too including the leveling up and souls revival etc. If you die during the battle with the demons, you will start from the last bonfire you visited.
At every bonfire, your health,stamina and spells will be restored and all the enemies excluding the bosses will be revived. So the struggle begins again and it will be like this till you make your way through without being killed. Other activities you can perform at bonfire are:
Leveling Up And Spells
This is where you can customize your character. You can call it the buy and sell store. The souls you have gathered can be spent to level up which is quite important while fighting with the demons specially the bosses.
You can then fill the free Attunement slots with the spells you want. Those spells are limited and if you run out of count, you will have to visit the bonfire to replenish them. You can equip more slots with the same spell to increase the number for example if you have 2 heal spells, you can caste it for 10 times rather than 5.
Humanity and Kindling Bonfires
You will start as a demon too. But with the passage of time you will gather humanity points which you can spend at the bonfires. Why one would want to be a human specially when the demons are the opponents? Well humans are more resistant to magical spells like curses while hollows are more sensitive.
Then in multiplayer, if you are human, you can invite others in your world and invade others’. But if you are a demon, you can’t act as a human host and can only join other worlds. Humanity comes handy specially in the boss fights.
You can also use the humanity to kindle the bonfires to increase the storage capacities. You can grab more items by kindling these bonfires. Estus Flasks for example are useful while you are up against the big demons.
How To Gain Humanity (by Arthur Martinz)
one of the easier ways is that you can find it on bodies as you explore dungeons. The other ways of attaining humanity are a combination of hard and easy methods.
Two ways require an online connection, as you can attain humanity by being summoned and helping someone defeat an area boss. You are also rewarded souls for helping them. The other way is by invading a person’s world and killing them.
The offline way of attaining humanity is by attacking and killing the human NPCs that are located around the world. This is a debatable method, as the NPCs will not respawn and you lose access to the items/spells/services that they provide.
You can also farm humanity off of rats, which are plentiful in the Depths. By starting at the first bonfire in the Depths, you can make a route that allows you to not only farm humanity off of the rats, but green titanite from slimes, and curse eyes from the cursed frogs.
Revival of Souls/Reverse Hollowing
Whenever you die in the game, you will return to the last bonfire in the hollow form. All your souls and humanity will be lost on the spot you died. You can recover it though if you manage to get to that point again.
The blood stain there will restore your lost resources. If you can’t reach that spot then there is a probability that those souls and humanity will be lost forever.
If this happens to you somehow then don’t be hasty and try luring the foes towards the bonfire so that you don’t die again which otherwise is more likely and you will be able to recover your souls.
These are the main functions of a bonfire except for saving your progress. Whenever you come across it, make sure that you use your resources wisely. For more help on Dark Souls, read our Weapons and Reinforcements, Magic, Items and Boss Strategy Guide.