Since combat is tied in with so much, I am going to limit this as to a brief overview of how combat works in Shards.
The shards combat system is a tactical, interactive system in which player skill plays an important role.
Skills, attributes, and equipment determine a baseline for your combat performance. This baseline is further influenced by the same statistics of your opponent. So in a completely passive sense you have a predictable trend that the fight will follow. This is similar to the DPS (Damage Per Second) mechanic used by most games as the derived statistic of utmost import in combat. This is where Shards segues into the tactical domain.
One of the trends which most games is that the DPS number tends to be the driving force behind everything else combat related. There’s that one item that gives the best DPS, that everyone has to get, in addition to an ability or set of abilities that provides the best combination for raising the DPS and keeping it that way. The result is that there is a small subset of items and abilities which get used, and everything else is either useless or place holder until you get those items. In WoW there are item sets and ability trees which must be used for each class/task that are just better than any other choice. In UO with its sandbox nature there may be any number of templates, but in reality in terms of effectiveness there is a small subset and when looking at the wide range of weapons and armor available, the final subset actually used is minute.
To address this the combat system is designed to cater to and accentuate playstyles, so rather than having a best skill and item configuration for your specific character, there is rather an equipment/skill/ and ability combination which is more enjoyable to your style of play, while still being effective. So if you favor hit and run tactics, positioning and strategy, or down and dirty brawling, you can play that way successfully.
The meat of the combat system sandwich
The passive aspects of combat give your character a baseline of expected performance. The passive aspects, being your equipment, attributes, and skills. That baseline will shift up or down depending on additional passive but dynamic aspects of your combat scenario such as your opponent, and their equipment, attributes and skills. So if you are playing as a knight, with full plate mail, shield and long sword your damage per hit, damage per second, or damage per minute, when factoring your skills and attributes in, all can be considered baseline performance stats. If you go up against another fighter their, skill, attributes, and equipment all together affect the damage you are capable of inflicting on them giving an adjustment to your baseline performance.
This “baseline” performance expectation is the meat of the system.
Using combat abilities, players are able to temporarily and sometimes dramatically alter the baseline. The abilities in Shards vary by execution, effect, and use conditions, so there are no global cooldowns, some abilities can be spammed constantly, others may have a cooldown, some may cost something others may only be used at certain times. What this means to players is that they can passively expect a certain level of performance by just sitting back, but they can expect better results through more interactive participation. Additionally by utilizing multiple methods of activation and effect of these abilities, we get around the spray and pray, or ability spam present in other games.
While you could go around spamming abilities as much as you can, you will have better results using tactical sense to figure out the best time to execute them, and what combination is most effective for your situation.
The surface is very straight forward and simple, but there is always more depth for those seeking to truly master their craft.