Gacha is a method where player can get various new weapons, cloths, badges, familiar shards and some miscellaneous items. There are usually 4 types of gacha to choose from: Gold Gacha, Witch Gacha, Prime Gacha and Lucky Gacha. During an event, Bloody Nightwish, Bloodline Gacha becomes available as well. Most of them requires crystals to activate. Only Lucky Gacha can be activated by Friend Points (FPs).
Gold Gacha gives player a 100% chance to get acquire rare equipment. The rarity of the equip ranges from 3 stars to 5 stars. Each activation of Gold Gacha costs 280 crystals. Most 5-starred Super Rare Equipment (indicated by gold stars coming out from an egg) found in Gold Gacha can be obtained in Equip Post.
Note that players can also get familiar shards instead of equipment. Collecting enough of these shards allows players to summon a familiar.
Prime Gacha is a cheaper version of Gold Gacha. Prime Gacha also allows players to have a chance to acquire different rare equipment. However, the rarity of the equip obtained ranges from 2 stars to 5 stars; it can be a waste of crystals when players get 2-starred items. Each activation of Prime Gacha costs 98 crystals.
Witch Gacha (formerly Devil Gacha) is a new type of Gacha that added in version 1.6.22. Witch Gacha gives player 10,000 Gold and equipment for each activation. Witch Gacha cost the same amount of crystals as Gold Gacha (280 crystals), and generally works the same as Gold Gacha. Most Super Rare equipment obtained from Witch Gacha are found in Equip Post as well.
Witch Gacha can be a reliable source to get a specific type familiar as there are events where Witch Gacha gives only familiar shards or familiar related items. Two specific type of familiar shards are more easily obtained as compared to other familiar shards and familiar related items.
Lucky Gacha is different from the other Gachas. Lucky Gacha gives mostly equipment and items that can be found in stages of the story mode, and during some events, event related items can be obtained as well. Items include those used for refining equipment and EXP Materials (Gold/Silver/Diamond Meow) which is for equip enhancement (level up). Once in a while, Raccoon Path familiar shards can be obtained.
180 FPs (Friend/Friendship Points) are required to activate Lucky Gacha. These FPs are obtained when players battle or when other players use their friend's character to help them battle.
While most items obtained from Lucky Gacha are not that useful, keep a lookout for equipment with a +1 symbol on the bottom right corner. Enhancing your main equipment with these gives your main equipment additional levels. Additional level for weapons provides an attack boost (0.2%) or ammo boost (0.2%) depending on the weapon, a HP boost (0.3%) for uniforms, and a speed boost (0.1%) for badges. These boosts are dependent on the base stats of the equipment.
Bloodline Gacha is available only during an event, Bloody Nightwish (as of vesion 3.4). It works the same as Gold Gacha. The only difference is better equipment (excluding basic set and V-set) obtained in Bloodline Gacha is mostly if not all different of those in Gold Gacha. These Super Rare Equipment cannot be found in Equip Post and requires event specific item Rurutiaza's Evil Mouth to refine.
The luckystar was introduced after the version 3.4. At the said version, players are now unavailable to open gacha directly using crystals, instead, you need to buy a luckystar before opening a gacha.
You can buy luckystar at the store > luckystar. The advantage of luckystar is you can stock it and use it when the item you want to get appeared in the featured.
You can also obtain luckystar at events (like Searing Path).
Obtaining Super Rare Equipment from Gold Gacha
Please check out this post by Guns Girl - School DayZ before proceeding on to the lengthy explanation I made.
The powerful artifacts the post is referring to is termed as Super Rare Equipment for this page. As mentioned in an above section, Super Rare Equipment are 5-starred equipment indicated by gold stars coming out from an egg when you activate a Gacha. What makes these equipment different is that you can refine them up to 6 stars and even up to 7 stars for certain equipment.
While some 5-starred equipment, those that can only be refined up to 5 stars, are termed as Super Rare Equipment in-game when obtained, these have purple stars coming out of the egg instead. Since these equipment can only be refined up to 5 stars, I see them as rare equipment instead.
What I write from this point on is my personal inference and assumption from their post.
My assumption is that when you have the game installed, the game server remembers every single Gold Gacha that you have activated based on your game ID number. It keeps track of the rarity of equipment you have for each row. Based on the post, a row is a sequence of 10 activation: 1st activation to 10th activation is a row, 11th activation to 20th activation is a row, 21th activation to 30 activation is a row, and so on. "Pray 10 times" is counted as a separate row from "Activate".
While there is always a possibility that players can obtain 10 Super Rare Equipment from 10 activation, the important point is when players get only rare equipment for the first 9 times in a particular row. The game does notice this fact. These players are guaranteed to get a Super Rare Equipment in their 10th activation for that specific row. Note that if a player has already obtained a Super Rare Equipment earlier in the row (e.g. 3rd or 7th activation), they are not guaranteed to get a Super Rare Equipment for the 10th activation for the row.
To make the point more apparent, the game does tell players in purple text that players can get a Super Rare Equipment in 3, 2 or 1 tries during the 8th, 9th, or 10th activation respectively for the particular row when players only get rare equipment for the first 7 activation in the row.
For "Pray 10 times", players are always guaranteed at least one Super Rare Equipment. The differences with 10 times "Activate" and "Pray 10 times" are: "Pray 10 times" requires players to have 2800 crystals immediately to activate while players can "Activate" 10 times at different timings whenever players have 280 crystals, "Pray 10 times" is always part of a row while "Activate" 10 times can be part of two different rows causing players to be confused when they fail to get a Super Rare Equipment.
For example, a player "Activate" 10 times is his/her 14th to 23rd activation as noted by the game. He/She does not get a Super Rare Equipment and thought the game cheated him/her. Note that 14th to 20th is part of a row while 21st to 23rd is part of another row, and this particular player has actually obtained a Super Rare Equipment during his 11th activation some time ago; the game remembers this. Since this player has already obtained a Super Rare Equipment for his row 11th to 20th, he is not guaranteed to get another Super Rare Equipment for this row. For row 21st to 30th, this player may not get a Super Rare Equipment during the first 9 tries as explained above. Taking note of these information, this particular player did not get cheated and is guaranteed to get a Super Rare Equipment if "Activate 7 more times.
For more extreme cases such as getting only two Super Rare Equipment in 37 "Activate", it might be that this player "Activate" 37 times is his/her 22nd to 58th activation, which is 4 different rows, and the player obtained a Super Rare Equipment during the 21st activation a while ago. The 2 Super Rare Equipment obtained are from rows 31st to 40th and 41st to 50th. Basing off the explanation I made above, the player is not guaranteed to get a Super Rare Equipment for his/her 22nd to 30th activation and 51st to 58th activation and thus, he/she only gets 2 Super Rare Equipment in 37 "Activate".
Basically, an advice I have when players have at least 2800 crystals and is going to activate Gold Gacha is to "Pray 10 times" instead. As mentioned, "Pray 10 times" always guarantee at least one Super Rare Equipment. At the very least, players will not feel that the game cheated them when failing to get a Super Rare Equipment for "Activate" 10 times.
This rule is implemented from version 1.7 as mentioned in the post. Bloodline Gacha follows this rule as well. This rule may hold true for Witch Gacha as well only when Witch Gacha does not only gives familiar shards or familiar related items. Due to my lack of usage of Prime Gacha, I cannot ascertain whether this rule works for it but I doubt it does since players are spending less crystals when they "Activate" 10 times for Prime Gacha.