Game crash during initial loading

---- Minecraft Crash Report ----
// Daisy, daisy...

Time: 2/20/20 1:01 AM
Description: Initializing game

java.lang.IllegalStateException: No renderer registered for mekanism:flame
at net.minecraft.client.renderer.entity.EntityRendererManager.(EntityRendererManager.java:228) ~[?:?] {re:classloading,pl:accesstransformer:B,xf:OptiFine:default}
at net.minecraft.client.Minecraft.(Minecraft.java:425) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.client.main.Main.main(SourceFile:166) ~[1.15.2-forge-31.1.0.jar:?] {re:classloading}
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_201] {}
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_201] {}
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_201] {}
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_201] {}
at net.minecraftforge.fml.loading.FMLClientLaunchProvider.lambda$launchService$0(FMLClientLaunchProvider.java:56) ~[forge-1.15.2-31.1.0.jar:31.1] {}
at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-5.0.0-milestone.4.jar:?] {}
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54) [modlauncher-5.0.0-milestone.4.jar:?] {}
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72) [modlauncher-5.0.0-milestone.4.jar:?] {}
at cpw.mods.modlauncher.Launcher.run(Launcher.java:81) [modlauncher-5.0.0-milestone.4.jar:?] {}
at cpw.mods.modlauncher.Launcher.main(Launcher.java:65) [modlauncher-5.0.0-milestone.4.jar:?] {}

A detailed walkthrough of the error, its code path and all known details is as follows:

-- Head --
Thread: Render thread
Stacktrace:
at net.minecraft.client.renderer.entity.EntityRendererManager.(EntityRendererManager.java:228)
at net.minecraft.client.Minecraft.(Minecraft.java:425)

-- Initialization --
Details:
Stacktrace:
at net.minecraft.client.main.Main.main(SourceFile:166)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at net.minecraftforge.fml.loading.FMLClientLaunchProvider.lambda$launchService$0(FMLClientLaunchProvider.java:56)
at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37)
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54)
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72)
at cpw.mods.modlauncher.Launcher.run(Launcher.java:81)
at cpw.mods.modlauncher.Launcher.main(Launcher.java:65)

-- System Details --
Details:
Minecraft Version: 1.15.2
Minecraft Version ID: 1.15.2
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_201, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 5263481864 bytes (5019 MB) / 6442450944 bytes (6144 MB) up to 6442450944 bytes (6144 MB)
CPUs: 8
JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx6G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
ModLauncher: 5.0.0-milestone.4+67+b1a340b
ModLauncher launch target: fmlclient
ModLauncher naming: srg
ModLauncher services:
/eventbus-2.0.0-milestone.1-service.jar eventbus PLUGINSERVICE
/forge-1.15.2-31.1.0.jar object_holder_definalize PLUGINSERVICE
/forge-1.15.2-31.1.0.jar runtime_enum_extender PLUGINSERVICE
/accesstransformers-2.0.0-milestone.1-shadowed.jar accesstransformer PLUGINSERVICE
/forge-1.15.2-31.1.0.jar capability_inject_definalize PLUGINSERVICE
/forge-1.15.2-31.1.0.jar runtimedistcleaner PLUGINSERVICE
/preview_OptiFine_1.15.2_HD_U_G1_pre5.jar OptiFine TRANSFORMATIONSERVICE
/forge-1.15.2-31.1.0.jar fml TRANSFORMATIONSERVICE
FML: 31.1
Forge: net.minecraftforge:31.1.0
FML Language Providers:
[email protected]
minecraft@1
Mod List:
forge-1.15.2-31.1.0-client.jar Minecraft {[email protected] COMMON_SETUP}
metalbarrels-2.1.jar Metal Barrels {[email protected] COMMON_SETUP}
Mekanism-1.15.2-9.9.9.401.jar Mekanism {[email protected] COMMON_SETUP}
forge-1.15.2-31.1.0-universal.jar Forge {[email protected] COMMON_SETUP}
MekanismTools-1.15.2-9.9.9.401.jar Mekanism: Tools {[email protected] COMMON_SETUP}
MekanismAdditions-1.15.2-9.9.9.401.jar Mekanism: Additions {[email protected] COMMON_SETUP}
Xaeros_Minimap_20.1.0_Forge_1.15.2.jar Xaero's Minimap {[email protected] COMMON_SETUP}
XaerosWorldMap_1.5.4_Forge_1.15.2.jar Xaero's World Map {[email protected] COMMON_SETUP}
MekanismGenerators-1.15.2-9.9.9.401.jar Mekanism: Generators {[email protected] COMMON_SETUP}
Hwyla-forge-1.10.7-B71_1.15.1.jar Waila {waila@version COMMON_SETUP}
jei-1.15.2-6.0.0.2.jar Just Enough Items {[email protected] COMMON_SETUP}
Launched Version: 1.15.2-forge-31.1.0
Backend library: LWJGL version 3.2.2 build 10
Backend API: GeForce GTX 960/PCIe/SSE2 GL version 4.6.0 NVIDIA 442.19, NVIDIA Corporation
GL Caps: Using framebuffer using OpenGL 3.0
Using VBOs: Yes
Is Modded: Definitely; Client brand changed to 'forge'
Type: Client (map_client.txt)
CPU: 8x AMD FX(tm)-8350 Eight-Core Processor
OptiFine Version: OptiFine_1.15.2_HD_U_G1_pre5
OptiFine Build: 20200219-183028
Render Distance Chunks: 12
Mipmaps: 4
Anisotropic Filtering: 1
Antialiasing: 0
Multitexture: false
Shaders: null
OpenGlVersion: 4.6.0 NVIDIA 442.19
OpenGlRenderer: GeForce GTX 960/PCIe/SSE2
OpenGlVendor: NVIDIA Corporation
CpuCount: 8

Turned over report to optifine as well.

Ehh. What optifine? There's no optifine for 1.15.2 forge. Also, you want to use some kind of pastebin for reports.

Remove optifine, optifine in its changelog mentions it is not compatible with forge. Not sure if it would work with just forge and vanilla or not, but I know at the very least it breaks a forge patch that allows mods to add custom entities without instantly crashing.

That'll teach me to finish reading the changelogs first.