Damage is a term in which it a successful connecting attack reduces the enemy's health and stun gauge, there are many types of damage in the Street Fighter series.
Types of damage
Normal damage is damage taken from an attack, some characters take lots of damage whereas others don't. There's also moves with lots of damage. Counter Hits tend to do more damage than regular attacks, do more Hitstun, and some attacks gain secondary properties such as Ibuki's Bonshogeri in Street Fighter X Tekken where a counter hit on a crouching character will cause a Stagger. Some games such as Street Fighter V has Crush Counters to lead to higher damage on connection.
Multi Hit Attacks
Some attacks such as Ibuki's close hard punch or light kick Tsumuji are multi hit attacks that once the sequence activates all attacks of the sequence will activate at it's timing when conditions are met. In this instance all hits of the sequence are usually done to add up to a certain number. For example Ibuki's Agemen to keep in line with most other medium attacks does a total of 60 damage in SFXTK. Both hits of the attack despite having different hit properties add up to 60, or in this case both hits do 30 damage each. By comparison Ibuki's own EX Neckbreaker does three hits compared to a single hit of her non EX version. The non EX version does a total of 160 damage in the aforementioned game while the three hits of the EX version do not activate unless connecting with the opponent and all three hits combine to do 180 damage total. In most cases one multi hit attacks do not add to the Damage Scaling chart but they might add to the Juggle total. Ibuki's close hard kick in SFXTK for example only counts as one point in damage scaling despite it doing two hits but adds two points to the juggling chart despite it being a single attack.
Attacks with Follow-Ups
Attacks such as Ibuki's Backhand Punch while seemingly similar to multi hit attacks actually are treated differently in game. Her Tsumuji for example, the light kick version only does two hits. The medium and hard actually have two follow up options that have their own hit properties and damage. In these cases the final hit when the player chooses to activate actually do add to the damage scaling chart. If Ibuki with no hits prior uses her hard kick Tsumuji and follows up with the standing kick followup and continues it the next hit will do 80% damage because the first two hits of her tsumuji is one point and the follow up uses it's own point. By comparison her EX Tsumuji despite doing more hits only does 1 point to the over all scaling because all hits happen by Ibuki herself without further player input.
Chip Damage as well as known as Block Damage, is damage taken when blocking an attack, only special moves can do chip damage, moves with multiple hits causes the most chip damage since chip damage only takes -1 point from the opponent's health bar, excluding some specials like Shoryuken or pre-Street Fighter II Turbo Head Press.
Street Fighter V changed how chip damage works, normal attacks lower health but leave provisional damage, specials work in the same way as previous games aside from not being able to get the KO with chip damage, as only Critical Arts such as Kachofugetsu can accomplish in this game.
Provisional Damage is damage that can recover back to pre-contact, This can only happen when attacks are released to an armored move, It is colored usually silver or it can be other colors depending on the game and recovers really slow. Whenever an opponent gets hit during the recover, it will cause the health to remain as it is. In some games provisional damage can occur simply by getting hit or taking chip damage. In team games provisional damage can usually be recovered when a character is tagged out and not in battle.
When the opponent's health reaches lower in capacity, the Damage Reduction gets higher. 75% health will start making the opponent reduce 10% damage, 50% health will get to 15% damage reduction, And 25% gets to 25% damage reduction. This is called "Toughness" in some games. Since characters have different health values, different characters benefit from this. The general rule is the more HP a character has the more they benefit. With balance changes some characters can enjoy damage reduction sooner. For example Ibuki launched in SFV with 900 damage, which meant her 50% damage reduction activated when she had 450 HP. Since then her health has been buffed into 925 which means she starts taking less damage at 463, making it a little harder to KO her.
Damage reduction stacks with Damage Scaling in games where both are present.
Exclusive to Dhalsim and a few specific moves on other characters, some attacks commit a fire status. In this state the opponent turns orange and their HP changes color and slowly dwindles until depleting. The opponent will not be knocked out when running out of health however and Dhalsim has to deliver the final blow. Hitting Dhalsim will stop this condition.
Exclusive to F.A.N.G and similar to Dhalsim's fire damage. Some of his attacks commit a Poison status, in this state the opponent turns purple and their HP changes color and slowly dwindles until depleting. His opponents will not be knocked out when running out of health however and F.A.N.G. has to deliver the final blow. Hitting F.A.N.G. will stop this condition.
Street Fighter games tend to have Stun mechanics. Every attack also does stun damage, which in many ways works opposite to HP. Unlike a health bar stun bars have to be filled 100% in modern games in order to activate. Once filled the character will get into a state where they can't be controlled. Some games don't have the mechanic, others do not have a visible bar, and others (such as Street Fighter V) have the bar visible at all times.
For most characters their HP bar tends to be higher than their stun bar, but there are some exceptions. For example in SFIV Ibuki has 900 HP but her stun health is actually 925. HP and stun health tend to go hand where the higher the HP the higher the stun meter, but there are some exceptions. Rufus for example has above average health but the exact same stun meter as Ibuki who is a low HP character in SFIV.
- Jin and Hulk are the only playable characters in the Marvel vs. Capcom series to deal chip damage from normal attacks.
- Balrog's Turn Punch damages can reach devastating numbers that tie to Ultras, although highly impractical. The Final Turn Punch reaching up to 560 of damage.
- If an attack is a deadly one hit, and gets to lower capacities, it will still do the same damage. So Ryu, with 1000 HP on full, will get 560 points of his health faded, leaving the 440 points left.
- It should be emphasized that F.A.N.G's poison damage has nothing to do with the character Poison.