Skills

Skills are important parts of characters that rate their ability in wide arrays of subjects and will give bonuses or debuffs based on the ranking of the skills and the situation in which they are used.

Upgrading:
Skills are not 'stackable' in that one cannot multiclass and gain higher ranking in a skill given by multiple classes, though skills can be advanced through the ranks by training or experience. Training can be done during time skips of one week or more, while experience is up to the GM's discretion of whether or not a character used a skill enough during a session to merit improvement. Both are rolled the same way, a DC of the related characteristic WITH FULL BONUSES, then if the roll FAILS to be under the DC, the skill may advance. One must fail one check to go from untrained to trained, three checks (In a row) to go from trained to proficient, and five (In a row) to go from proficient to expertise.

Untrained:
The default state for all skills, results in somewhat difficulty when using an untrained skill.

Trained:
The state most given early on by classes, races, etc, removes the difficulty status

Proficient:
The state usually given by mid-late levels by classes, or by training/experience, gives a bonus based on the highest level of any classes. (Bonus is removed from rolled value.)

LVL 4: -3

LVL 8: -5

LVL 12: -8

LVL 16: -10

LVL 20: -15

Expertise:
The state that usually must be earned, or is given by very late class levels, gives advantage to rolls using the skill, and doubles the bonus from proficiency. Though if the skill is not used for 3 sessions expertise will be demoted to proficient.