The skill entry in SkillData.txt located in the mod's Stats/Generated/Data folder is almost a complete copy of the Rain_Water skill entry.
new entry "Heal_Rain_Water"
type "SkillData"
data "SkillType" "Rain"
data "Ability" "Defensive"
data "Element" "Water"
data "ActionPoints" "4"
data "Cooldown" "6"
data "ChargeDuration" "0"
data "Lifetime" "5"
data "SurfaceType" "Water"
data "SurfaceLifetime" "12000"
data "SurfaceStatusChance" "100"
data "SkillProperties" "Consume,100,5,SKILLBOOST_AoE_Healing_Rain;Douse,-1,5,,70"
data "TargetRadius" "15"
data "UseCharacterStats" "No"
data "UseWeaponDamage" "No"
data "AreaRadius" "20"
data "TotalSurfaceCells" "125"
data "SurfaceGrowStep" "5"
data "SurfaceGrowInterval" "150"
data "Icon" "Skill_Water_Rain"
data "DisplayName" "Rain_Water_DisplayName"
data "DisplayNameRef" "Rain"
data "Description" "Rain_Water_Description"
data "DescriptionRef" "Create water surfaces."
data "StatsDescription" "Rain_Water_StatsDescription"
data "StatsDescriptionRef" "Radius: [1]<br>Duration: [2]<br><br>Creates water puddles on terrain, douses fires, and makes characters wet. Water surfaces can be electrified."
data "StatsDescriptionParams" "AreaRadius;Lifetime"
data "FXScale" "100"
data "PrepareAnimationInit" "skill_rain_start"
data "PrepareAnimationLoop" "skill_rain_loop"
data "PrepareEffect" "FX_Skills_Water_Rain_Prepare_A"
data "CastAnimation" "skill_rain_cast"
data "CastTextEvent" "cast"
data "CastEffect" "FX_Skills_Water_Rain_Cast_A"
data "TargetEffect" "FX_GP_Target_Water_A"
data "Magic Cost" "1"
data "RainEffect" "FX_Skills_Water_Rain_A"
data "Atmosphere" "Rain"
data "ConsequencesStartTime" "1000"
data "Skillbook" "SKILLBOOK_Heal_Rain_Water"
new entry "Heal_Rain_Water_3"
type "SkillData"
using "Heal_Rain_Water"
data "Level" "3"
The key difference with this skill compared to the normal Rain is this line-
data "SkillProperties" "Consume,100,5,SKILLBOOST_AoE_Healing_Rain;Douse,-1,5,,70"
Instead of Rain, it does the Consume status effect.
What does the Consume status effect do? Anything we want, since it applies the status effect we specify (SKILLBOOST_AoE_Healing_Rain) when initially cast.
Status effects are defined in the Potion.txt of the Stats/Generated/Data/ folder. Here's my mod's entry for SKILLBOOST_AoE_Healing_Rain-
new entry "_SkillBoost"
type "Potion"
new entry "SKILLBOOST_AoE_Healing_Rain"
type "Potion"
using "_SkillBoost"
data "Vitality" "5"
data "Duration" "1"
The durations of the Skill and the Status effect are important. Basically, the Healing Rain applies its status once a round for 5 turns (the Skill Duration). The status, when it's applied, heals and lasts for the current turn only (Duration 1). This results in the heal being applied 5 times. If the duration is increased, then the effect should last a bit even after the Skill's duration is over.