diff --git a/src/main/java/com/volmit/iris/generator/actuator/IrisBiomeActuator.java b/src/main/java/com/volmit/iris/generator/actuator/IrisBiomeActuator.java
index 6b1a315c0..245d34fbe 100644
--- a/src/main/java/com/volmit/iris/generator/actuator/IrisBiomeActuator.java
+++ b/src/main/java/com/volmit/iris/generator/actuator/IrisBiomeActuator.java
@@ -2,6 +2,7 @@ package com.volmit.iris.generator.actuator;
 
 import com.volmit.iris.nms.INMS;
 import com.volmit.iris.object.IrisBiome;
+import com.volmit.iris.object.IrisBiomeCustom;
 import com.volmit.iris.scaffold.engine.Engine;
 import com.volmit.iris.scaffold.engine.EngineAssignedActuator;
 import com.volmit.iris.scaffold.hunk.Hunk;
@@ -13,8 +14,11 @@ import com.volmit.iris.util.RNG;
 import org.bukkit.block.Biome;
 
 public class IrisBiomeActuator extends EngineAssignedActuator<Biome> {
+    private final RNG rng;
+
     public IrisBiomeActuator(Engine engine) {
         super(engine, "Biome");
+        rng = new RNG(engine.getWorld().getSeed() + 243995);
     }
 
     @Override
@@ -35,7 +39,8 @@ public class IrisBiomeActuator extends EngineAssignedActuator<Biome> {
                     {
                         try
                         {
-                            Object biomeBase = INMS.get().getCustomBiomeBaseFor(getDimension().getLoadKey()+":"+ib.getCustom().getId());
+                            IrisBiomeCustom custom = ib.getCustomBiome(rng, x, 0, z);
+                            Object biomeBase = INMS.get().getCustomBiomeBaseFor(getDimension().getLoadKey()+":"+custom.getId());
                             ((BiomeGridHunkView)h).forceBiomeBaseInto(x, 0, z, biomeBase);
 
                             for (int i = 0; i < h.getHeight(); i++) {
@@ -46,7 +51,7 @@ public class IrisBiomeActuator extends EngineAssignedActuator<Biome> {
                         catch(Throwable e)
                         {
                             e.printStackTrace();
-                            Biome v = ib.getSkyBiome(RNG.r, x, 0, z);
+                            Biome v = ib.getSkyBiome(rng, x, 0, z);
                             for (int i = 0; i < h.getHeight(); i++) {
                                 h.set(xxf, i, zzf, v);
                             }
@@ -55,7 +60,7 @@ public class IrisBiomeActuator extends EngineAssignedActuator<Biome> {
 
                     else
                     {
-                        Biome v = ib.getSkyBiome(RNG.r, x, 0, z);
+                        Biome v = ib.getSkyBiome(rng, x, 0, z);
                         for (int i = 0; i < h.getHeight(); i++) {
                             h.set(xxf, i, zzf, v);
                         }
diff --git a/src/main/java/com/volmit/iris/object/IrisBiome.java b/src/main/java/com/volmit/iris/object/IrisBiome.java
index 32d55ac23..ed6aab2fe 100644
--- a/src/main/java/com/volmit/iris/object/IrisBiome.java
+++ b/src/main/java/com/volmit/iris/object/IrisBiome.java
@@ -32,8 +32,9 @@ public class IrisBiome extends IrisRegistrant implements IRare {
     private String name = "A Biome";
 
     @DontObfuscate
+    @ArrayType(min = 1, type = IrisBiomeCustom.class)
     @Desc("If the biome type custom is defined, specify this")
-    private IrisBiomeCustom custom;
+    private KList<IrisBiomeCustom> customDerivitives;
 
     @DontObfuscate
     @Desc("Entity spawns to override or add to this biome. Anytime an entity spawns, it has a chance to be replaced as one of these overrides.")
@@ -201,7 +202,7 @@ public class IrisBiome extends IrisRegistrant implements IRare {
 
     public boolean isCustom()
     {
-        return getCustom() != null;
+        return getCustomDerivitives() != null && getCustomDerivitives().isNotEmpty();
     }
 
     public double getGenLinkMax(String loadKey) {
@@ -535,6 +536,14 @@ public class IrisBiome extends IrisRegistrant implements IRare {
         return biomeSkyScatter.get(getBiomeGenerator(rng).fit(0, biomeSkyScatter.size() - 1, x, y, z));
     }
 
+    public IrisBiomeCustom getCustomBiome(RNG rng, double x, double y, double z) {
+        if (customDerivitives.size() == 1) {
+            return customDerivitives.get(0);
+        }
+
+        return customDerivitives.get(getBiomeGenerator(rng).fit(0, customDerivitives.size() - 1, x, y, z));
+    }
+
     public KList<IrisBiome> getRealChildren(DataProvider g) {
         return realChildren.aquire(() ->
         {
@@ -564,6 +573,7 @@ public class IrisBiome extends IrisRegistrant implements IRare {
         return new KList<String>(m);
     }
 
+    //TODO: Test
     public Biome getGroundBiome(RNG rng, double x, double y, double z) {
         if (biomeScatter.isEmpty()) {
             return getDerivative();
diff --git a/src/main/java/com/volmit/iris/object/IrisBlockDrops.java b/src/main/java/com/volmit/iris/object/IrisBlockDrops.java
index 9f8edc7dd..67d7197f8 100644
--- a/src/main/java/com/volmit/iris/object/IrisBlockDrops.java
+++ b/src/main/java/com/volmit/iris/object/IrisBlockDrops.java
@@ -65,6 +65,8 @@ public class IrisBlockDrops {
         return false;
     }
 
+    // TODO: WARNING USES RNG.R
+    @Deprecated
     public void fillDrops(boolean debug, KList<ItemStack> d) {
         for (IrisLoot i : getDrops()) {
             if (RNG.r.i(1, i.getRarity()) == i.getRarity()) {
diff --git a/src/main/java/com/volmit/iris/object/IrisDimension.java b/src/main/java/com/volmit/iris/object/IrisDimension.java
index 938cde1f7..0664fdb65 100644
--- a/src/main/java/com/volmit/iris/object/IrisDimension.java
+++ b/src/main/java/com/volmit/iris/object/IrisDimension.java
@@ -468,19 +468,23 @@ public class IrisDimension extends IrisRegistrant {
             if(i.isCustom())
             {
                 write = true;
-                File output = new File(datapacks, "iris/data/" + getLoadKey() + "/worldgen/biome/" + i.getCustom().getId() + ".json");
 
-                if(!output.exists())
+                for(IrisBiomeCustom j : i.getCustomDerivitives())
                 {
-                    changed = true;
-                }
+                    File output = new File(datapacks, "iris/data/" + getLoadKey() + "/worldgen/biome/" + j.getId() + ".json");
 
-                Iris.verbose("    Installing Data Pack Biome: " + output.getPath());
-                output.getParentFile().mkdirs();
-                try {
-                    IO.writeAll(output, i.getCustom().generateJson());
-                } catch (IOException e) {
-                    e.printStackTrace();
+                    if(!output.exists())
+                    {
+                        changed = true;
+                    }
+
+                    Iris.verbose("    Installing Data Pack Biome: " + output.getPath());
+                    output.getParentFile().mkdirs();
+                    try {
+                        IO.writeAll(output, j.generateJson());
+                    } catch (IOException e) {
+                        e.printStackTrace();
+                    }
                 }
             }
         }