Iblis mod add a two separated attribute systems. One set of attributes can be raised using vanilla Minecraft experience levels (which I will call "characteristics") and second set is trainable skills.

Additional info about mod at Wiki page: https://github.com/Foghrye4/Iblis/wiki

See also: https://minecraft.curseforge.com/projects/level-up "Level Up!" mod if you don't like a system provided by Iblis.

Characteristics

Each level of characteristic require same amount of experience levels of player for raise as level value itself.

For example, to raise "Max health points 2" -> "Max health points 3" you need a 2 experience levels.

Here is a list of characteristics:

Max health points
Melee damage reduction
Fire damage reduction
Projectile damage reduction
Explosion damage reduction - reduce incoming damage by characteristic value before armor protection takes effect.
Damage base
Attack speed
Knockback resistance
Luck - alongside loot bonuses also affect critical strike chance of shotgun.
Intelligence - added to all skills when they are used.
Gluttony - control amount of food which can be devoured.

Skills

Each skill require special condition to be raised. Each point of skill raise parent skill at 1/4 of point and wisdom at 1/16 of point. Effective skill value is a sum of skill value itself + parent skill + wisdom + intelligence. Wherefore experienced armourer is able to effectively use sword and vice-versa.

Swordsmanship

Raised each successful attack with any tool, which grant bonus to attack damage. Amount of points depends from target armor value. Full skill value is added to attack damage.

Archery

Raised each successful attack with bow.
Full skill value affect arrow damage as: damage=damage*(full_skill_value+0.2)

Sharpshooting

Affect accuracy of shotgun and critical strike chance of shotgun (if above 8).

Armorsmith

Raised each time item with armor bonus is crafted. Affect armor and armor toughness bonus of item. Works with mod items if mod load recipes before this mod.

Weaponsmith

Raised each time item with damage bonus is crafted. Affect damage bonus of swords and tools. Works with mod items if mod load recipes before this mod.

Mechaincs

Raised each time item with mechanism (bow, crossbow, clock, shotgun) is crafted. Affect damage bonus of bow, crossbow and shotgun.

Medical aid

Affect amount of HP healed with medkit.

Digging

Affect digging speed with proper tool.

Running

Multiply speed with a factor x(1.0 + value). To control sprinting speed press "forward" and then click shortly "sprint" button. You will start running slightly faster (with vanilla sprint speed). After that you may press and hold "sprint" button and you will quickly speed up. A more distance you made while sprinting, a more skill will be raised.

Jumping

Hold [CTRL] or sprinting button to jump higher. Trained every jump. Trained 2x faster with high jumps.

Falling

Reduce damage from falling by its own value. Trained when player fell from height of 2 blocks or above.

GUI

Mod add two buttons as seen on screenshot:

They are visible only in survival mode. First one (with arm icon) leads to characteristics GUI. Second one (with blue brain icon) leads to skills GUI.

Characteristics GUI

Skills GUI

Headshots.

With Iblis mod launched, every attack with projectile entities (such as arrows) or with shotgun directed to monster head will raise out-coming damage 4x times.

Books: Guide and Adventurer diary.

Adventurer diary is item, which could be used by players to exchange wisdom and to save skills beyond a point of death. Each time diary is crafted it store skills gained by player and with penalty of 30% player could restore his skills after death.

Guide books is a source of knowledge obtained via loot chests in dungeons.

Player zombie.

Whenever player dies instead of dropping items it spawns zombie with player equipment. Killing this zombie release all experience levels (including whose whom was spent on characteristics) in XP orbs.

Shotgun.

This mod adds a shotgun. Sharpshooting skill affect accuracy and, together with luck, critical chance of shotgun (increasing damage 100x). Also accuracy affected by recoil and sneaking state of a player.

Crafting recipe:

Any vanilla type wood planks would work.

Medkit.

Medkit is used to heal yourself as a cheap alternative of regeneration potion. After use medkit will add a regeneration effect to player which will last 30 seconds and heal amount of HP depending from player medical aid skill. At skill level 0 it will heal 1 heart. At skill level 1 it will heal 2 hearts. At skill level 9 it will heal 20 hearts.

Crafting compounded from two stages:

Stage 1:

Stage 2:

Steel ingot texture used in this mod is taken from Mekanism. Official website: http://aidancbrady.com/mekanism/