Bonfires are checkpoints that appear throughout the game and have various uses. Most areas in the game have bonfires other than Quelaag's Domain, Darkroot Basin, Crystal Cave and the New Londo Ruins (upper).
Bonfires that are previously not yet encountered will be at unlit state (except Firelink Shrine which is already lit). Unlit bonfires may be lit to be able to rest at it. Bonfires that were lit but become extinguished may be caused by the death of its Fire Keeper (example: Anastascia's death makes Firelink Shrine's bonfire unaccessible). Lighting a bonfire doesn't make you will respawn at the last bonfire you lit, but resting will. Beware, some bonfire may make you doomed if that is the last bonfire you rested at.
Resting at a bofire will:
- respawn all enemies
- refill your Estus Flask (the refill amount varies; depending upon its kindle level)
- fully heals your character
- cures any status ailments
Resting at a bofire will not:
- respawn non-respawning enemies (mini-bosses) -- like various Black Knights throughout the game, Hydra at Darkroot Basin, Berenike Knight at Undead Parish -- and bosses
- make you immune from enemy attacks which coming to you
- make you immune from being summoned and invaded (online interaction)
- break your Cursed status
When resting at a bonfire, you can:
Use souls to increase your attributes of your choice. One attribute increment increases your soul level by one.
Souls required to level up are increasing progressively.
Reinforce Weapon / Armor
This menu will appear once you have got acquired the Weapon Smithbox. It is a Key item which is only need to be bought once per playthrough and can be used multiple times. (That means you will lose this access if you progress your game through NG and beyond, and must be re-purchased again.) You can buy the Weapon Smithbox from Blacksmith Andre for 2000 souls.
It allows weapon and armour reinforcement without visiting a blacksmith. You will still need to visit the corresponding blacksmith to ascend a weapon.
This menu will appear once you have got acquired the Repairbox. It is a Key item which is only need to be bought once per playthrough and can be used multiple times. You can buy the Repairbox from Undead Male Merchant for 3000 souls or Blacksmith Andre for 2000 souls.
It allows weapon and armour repairment without visiting a blacksmith or using Repair Powder. However, it still requires souls to repair, as same as visiting a blacksmith.
This menu will appear once you have at least one slot of Attunement and one spell.
It allows your character to "remember" a spell until you decide to take it out at the next bonfire rest.
Access Bottomless Box
This menu will appear once you have got acquired the Bottomless Box. It is a Key item which is only need to be bought once and for the rest of playthroughs. (That means you will not lose this access if you progress your game through NG and beyond.) You can buy the Bottomless Box from Undead Male Merchant or Domnhall of Zena for 1000 souls.
It allows you to store things infinitely to keep your inventory clean from clutter.
This menu will appear once you have got acquired the Lordvessel. It is a Key item which is given once per playthrough.
It allows you to teleport to another bonfire location. Not all bonfires are available to teleport, and bonfires that teleported to may not be able to teleport you back.
For example: teleporting to Painted World of Ariamis' bonfire is possible, but you are not possible to teleport from this bonfire. Another example: teleporting to unlit bonfire (which was lit but its Fire Keeper is dead) is possible, but you are not possible to teleport from this bonfire until it is lit again.
You only can kindle bonfires when in Human form. You can kindle a bonfire more than once once you have got acquired the Rite of Kindling. It is a Key item which is gotten once per playthrough. When a bonfire is kindled, you will get more Estus Flask amount than you normally would.
You can become a Human mutiple times (in case you have gone Hollow again after being a Human), only if you are not Cursed. Reverse Hollowing consumes one liquid Humanity. You will always start the playthrough as a Hollow, no matter if you were at Human form when you have got beaten the last playthrough.
Being a Human, you are able to interact with the online Dark Souls world: summon a player to assist or PvP, but also susceptible to random invasions.