Soul Points were introduced as an Anti-Cheat Measure in the 2005 Summer Update to prevent macro users from endlessly creating runes. Soul points are required for most enchant spells (Enchant Staff is an exception), as well as conjuring items and creating runes.
Free Account characters have a maximum of 100 soul points and Premium Account characters have a maximum of 200. Soul points restore automatically over time when hunting and sleeping.
You can see your current amount of soul points by your Inventory, below the ring slot.
Using Soul Points
Soul points get used up when creating runes, conjuring items or enchanting gems. Every enchant/rune spell requires a number of soul points for it to happen. This can range from 1 to 5 soul points per spell. This also means that as knights are the only profession who as of now cannot create runes or conjure items, they do not make any use of their soul points.
If you do not have sufficient soul points to cast a spell, it will take no effect until you regenerate enough of them again.
Soul Points Table: Runes
Soul Points Table: Conjuring/Supply Spells
Soul Points: Enchanting
Premium Account Sorcerers and Druids have the ability to enchant small gems and charge them with elemental properties. These enchantments can only take place at Holy Shrines (usually located in city temples), which only mages of level 30 or higher may enter.
In the process, Druids can create small enchanted sapphires (ice element) and small enchanted emeralds (earth element), while Sorcerers create small enchanted rubies (fire element) and small enchanted amethyst (energy element). The enchantment costs 300 mana points and 2 soul points.
For more information see: Enchanting.
Regenerating Soul Points
There are two ways to regenerate Soul Points:
Firstly, Soul Points are generated by hunting Creatures around Tibia. However, this is dependant on player's level, because in order to regenerate Soul Points, hunted monsters have to yield experience equal to or higher than player's level.
This means that a level 50 Paladin will be regenerating their Soul Points after killing a Cyclops (Cyclops yield 150 exp.), but killing a Wolf (18 exp.) will have no effect. Note that the stamina bonus experience does count towards this effect. This means that as long as you receive enough experience from killing a monster, even if it was only due to bonus stamina, your Soul Points will still regenerate. However, the experience from killing several creatures at the same time does not stack (e.g. using a great fireball rune on 10 snakes will count the same as killing only one snake).
Killing a monster will trigger Soul Points to regenerate for 4 minutes. If in that time the player kills another monster, the 4 minute counter will reset. However, killing a monster that yields less experience than the player's level will prevent the regeneration from happening until a strong enough creature is killed again.
Regular characters regenerate Soul Points at a rate of 1 Soul Point every 2 minutes, while Promoted characters' Soul Points regenerate at a rate of 1 Soul Point every 15 seconds (total of 16 Soul Points in 4 minutes).
Secondly, Premium characters can regenerate their Soul Points by sleeping in a bed. This method does not require killing creatures and will regenerate 1 Soul Point every 15 minutes.