Simulacra works like a character skin, and are obtainable when you get an SR weapon or higher. You can select them to change your character's apperance into them for exploration, but the game will automatically switch to your default character during cutscenes.
You can view more information about each character on the Simulacra screen to view their log, hear character voice, or give them gifts.
Giving them gifts increases their awakening points and gives a reward once you reach 200/600/1200/2000/3000/4000 points.
What is Nature?
Equipping/using the character's appearance doesn't give any kind of status boost, but they do have exclusive skills that unlock at 1200 and 4000 points called "Nature".
Nature skills aren't necessarily related to the weapon they are from. They are mostly passive effects that can help during battle or exploration.
You have the option to hide the Simulacra appearance if you want to get the benefit of the skill without using their appearance when exploring.
A gamer with a high level of Talent and Wit, Zero / Rei uses the Negating Cube as his main weapon.
Nature
Zero: Accurate Calculation
When Zero uses a weapon skill, reduce cooldown time for Relics in cooldown by 1.5 seconds. Can only activate for the same weapon 1 time every 5 seconds.
Zero: Overall Planning
When Zero uses a weapon skill, reduce cooldown time for Relics in cooldown by 3 seconds. Can only activate for the same weapon 1 time every 5 seconds.
Good at solving riddles and playing tricks, Samir/Semir is terrible at Fishing but is quick to Take Action.
Nature
Samir: Trickery
Grant 1 stack of Concentration for every 4 seconds when Samir receives no damage. Each stack increases damage dealt by 3%, and can stack up to 4 times. After being hit, Samir loses 1 stack of Concentration, up to 1 stack per 1 second.
Samir: Shadow
Grant 1 stack of Concentration for every 4 seconds when Samir receives no damage. Each stack increases damage dealt by 4%, and can stack up to 5 times. After being hit, Samir loses 1 stack of Concentration, up to 1 stack per 2 seconds.
An often Conflicted character that isn't good with her Memory or Communication, Huma / Schumer often Stares into space or Reads.
Nature
Huma: Fortitude
Each time Huma receives damage, gain 1 Fortitude mark and gain 1 more Fortitude mark if it is flame damage, up to 1 time per 1 second and 12 stacks in total. Upon using a weapon skill, use all Fortitude marks and gain an HP shield equal to the number of marks x0.4% HP for 12 seconds. If Fortitude marks are used when the effect is stacked up to the maximum, then gain an HP shield equal to the number of marks x0.6% HP.
Huma: Iron Curtain
Each time Huma receives damage, gain 1 Fortitude mark and gain 1 more Fortitude mark if it is flame damage, up to 1 time per 1 second and 12 stacks in total. Upon using a weapon skill, use all Fortitude marks and gain an HP shield equal to the number of marks x0.6% HP for 12 seconds. If Fortitude marks are used when the effect is stacked up to the maximum, then gain an HP shield equal to the number of marks x0.9% HP.
While not Courageuos or Perceptive, Coco is both Vigorous and Crafty with a love for Penguins.
Nature
Cocoritter: Assistance
When Cocoritter uses a support weapon, increase healing effects she inflicts on others and receives by 20%.
Cocoritter: Trust
When Cocoritter uses a support-type weapon, the effects of healing and receiving healing are increased by 20%, and when the discharge skills or weapon skills of the support-type weapon are used, the ATK of the friendly armies around you will increase by 15% and lasts for 5 seconds.