It's super helpful that you've provided a crash log!
I'm looking for a fix at the moment.

Fixed now!

Playing card "Not Fission" causes nullpointer. It's a non upgraded version, I have 3 orb slots(for blades) and it crashes with or without a havoc blade channeled.

03:48:57.947 ERROR core.CardCrawlGame> Exception caught
java.lang.NullPointerException: null
at blademaster.actions.BetterFissionAction.update(BetterFissionAction.java:25) ~[Blademaster.jar:?]
at com.megacrit.cardcrawl.actions.GameActionManager.update(GameActionManager.java:155) ~[?:?]
at com.megacrit.cardcrawl.rooms.AbstractRoom.update(AbstractRoom.java:279) ~[?:?]
at com.megacrit.cardcrawl.dungeons.AbstractDungeon.update(AbstractDungeon.java:2552) ~[?:?]
at com.megacrit.cardcrawl.core.CardCrawlGame.update(CardCrawlGame.java:878) ~[?:?]
at com.megacrit.cardcrawl.core.CardCrawlGame.render(CardCrawlGame.java:429) [?:?]
at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:225) [?:?]
at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:126) [desktop-1.0.jar:?]

Looks like Blade Dance is being buggy again. Here's the error log:

21:46:41.725 INFO duelistmod.DuelistMod> Card Used: Blade Dance+
Exception: java.lang.NullPointerException
21:46:41.732 ERROR core.CardCrawlGame> Exception caught
java.lang.NullPointerException: null
at blademaster.cards.BladeDance.use(BladeDance.java:66) ~[Blademaster.jar:?]
at com.evacipated.cardcrawl.mod.hubris.patches.ZylophonePatch$MultiUse.use(ZylophonePatch.java:51) ~[Hubris.jar:?]
at com.megacrit.cardcrawl.characters.AbstractPlayer.useCard(AbstractPlayer.java:1594) ~[?:?]
at com.megacrit.cardcrawl.actions.GameActionManager.getNextAction(GameActionManager.java:297) ~[?:?]
at com.megacrit.cardcrawl.actions.GameActionManager.update(GameActionManager.java:159) ~[?:?]
at com.megacrit.cardcrawl.rooms.AbstractRoom.update(AbstractRoom.java:279) ~[?:?]
at com.megacrit.cardcrawl.dungeons.AbstractDungeon.update(AbstractDungeon.java:2552) ~[?:?]
at com.megacrit.cardcrawl.core.CardCrawlGame.update(CardCrawlGame.java:878) ~[?:?]
at com.megacrit.cardcrawl.core.CardCrawlGame.render(CardCrawlGame.java:429) [?:?]
at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:225) [?:?]
at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:126) [desktop-1.0.jar:?]
Controllers: removed manager for application, 0 managers active
Game closed.

As for Blade Dance, it crashes if you have Infinite/ Hubris. I'll disable the card if you have either of those tomorrow. The fission fix is coming tomorrow too.

Bladedance also crashes with just BaseMod, StSLib, ReplayTheSpire and Bladedancer. In both cases you are iterating over AbstractDungeon.player.orbs without checking if the orb is null. Might just be that, since other mods like the disciple check for null when they use that collection.

Has fission been fixed?
I downloaded the mod today and I'm getting the same error as Razuhl above.

Got this error when playing IcyWind. I wasn't in a stance and had no charges.
Exception: java.lang.NullPointerException
03:23:19.526 ERROR core.CardCrawlGame> Exception caught
java.lang.NullPointerException: null
at blademaster.cards.IcyWind.use(IcyWind.java:44) ~[Blademaster.jar:?]
at com.megacrit.cardcrawl.characters.AbstractPlayer.useCard(AbstractPlayer.java:1594) ~[?:?]
at com.megacrit.cardcrawl.actions.GameActionManager.getNextAction(GameActionManager.java:297) ~[?:?]
at com.megacrit.cardcrawl.actions.GameActionManager.update(GameActionManager.java:151) ~[?:?]
at com.megacrit.cardcrawl.rooms.AbstractRoom.update(AbstractRoom.java:279) ~[?:?]
at com.megacrit.cardcrawl.dungeons.AbstractDungeon.update(AbstractDungeon.java:2552) ~[?:?]
at com.megacrit.cardcrawl.core.CardCrawlGame.update(CardCrawlGame.java:878) ~[?:?]
at com.megacrit.cardcrawl.core.CardCrawlGame.render(CardCrawlGame.java:429) [?:?]
at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:225) [?:?]
at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:126) [desktop-1.0.jar:?]

game crashed after fighting grand snecko.

14:22:30.338 INFO monsters.AbstractMonster> Disposed Texture: Grand Snecko
14:22:30.604 INFO basemod.BaseMod> publish post combat
14:22:30.604 INFO basemod.BaseMod> End of battle: Clearing players minions.
14:22:30.608 INFO helpers.ImageMaster> [WARNING] No image at runesmith/images/orbs/Medicinae.png
14:22:32.098 INFO dungeons.AbstractDungeon> UNSPECIFIED CASE: NONE
14:22:32.109 INFO core.CardCrawlGame> Exception occurred in CardCrawlGame render method!
14:22:32.109 ERROR core.CardCrawlGame> Exception caught
java.lang.NullPointerException: null
at blademaster.cards.Strike.update(Strike.java:82) ~[Blademaster.jar:?]
at com.megacrit.cardcrawl.cards.CardGroup.update(CardGroup.java:656) ~[?:?]
at com.megacrit.cardcrawl.core.OverlayMenu.update(OverlayMenu.java:60) ~[?:?]
at com.megacrit.cardcrawl.dungeons.AbstractDungeon.update(AbstractDungeon.java:2629) ~[?:?]
at com.megacrit.cardcrawl.core.CardCrawlGame.update(CardCrawlGame.java:879) ~[?:?]
at com.megacrit.cardcrawl.core.CardCrawlGame.render(CardCrawlGame.java:427) [?:?]
at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:225) [?:?]
at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:126) [desktop-1.0.jar:?]
Controllers: removed manager for application, 0 managers active
14:22:32.138 INFO core.CardCrawlGame> PAUSE()
14:22:32.139 INFO core.CardCrawlGame> Game shutting down...
14:22:32.140 INFO core.CardCrawlGame> Flushing saves to disk...
14:22:32.143 INFO helpers.FileSaver> Save thread interrupted!

Just got a hilarious interaction with another mod.

Play 1: Unrelenting [Power, The Slumbering] - The next >0-cost card you play gets repeated until you run out of energy.
Play 2: Reversal

ENEMY FULL-PARTY WIPE VIA INFINITE LOOP

Also, Ki Barrier isn't properly displaying its block generation (probably just a typo in the code).

I cannot confirm for sure that this caused the CTD but I am quite confident I got a CTD because of Mayhem trying to cast a combo/fury card at the start of my turn.

Using a few other mods too, but confirmed that using this mod with them causes end of combat reward screen have the 2 top items uninteractable. Maybe an UI problem.

13:03:15.248 INFO basemod.BaseMod> publish on card use: blademaster:Reversal
13:03:15.248 INFO core.CardCrawlGame> Exception occurred in CardCrawlGame render method!
13:03:15.255 ERROR core.CardCrawlGame> Exception caught
java.lang.NullPointerException: null
at blademaster.cards.Reversal.use(Reversal.java:70) ~[Blademaster.jar:?]
at com.megacrit.cardcrawl.characters.AbstractPlayer.useCard(AbstractPlayer.java:1698) ~[?:?]
at blademaster.characters.BlademasterCharacter.useCard(BlademasterCharacter.java:169) ~[Blademaster.jar:?]
at com.megacrit.cardcrawl.actions.GameActionManager.getNextAction(GameActionManager.java:358) ~[?:?]
at com.megacrit.cardcrawl.actions.GameActionManager.update(GameActionManager.java:175) ~[?:?]
at com.megacrit.cardcrawl.rooms.AbstractRoom.update(AbstractRoom.java:325) ~[?:?]
at com.megacrit.cardcrawl.dungeons.AbstractDungeon.update(AbstractDungeon.java:2532) ~[?:?]
at com.megacrit.cardcrawl.core.CardCrawlGame.update(CardCrawlGame.java:871) ~[?:?]
at com.megacrit.cardcrawl.core.CardCrawlGame.render(CardCrawlGame.java:419) [?:?]
at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:225) [?:?]
at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:126) [?:?]
13:03:15.288 INFO core.CardCrawlGame> PAUSE()
13:03:15.292 INFO core.CardCrawlGame> Game shutting down...
13:03:15.298 INFO core.CardCrawlGame> Flushing saves to disk...
13:03:15.304 INFO helpers.FileSaver> Save thread interrupted!
13:03:15.305 INFO core.CardCrawlGame> Shutting down publisher integrations...
13:03:15.334 INFO core.CardCrawlGame> Flushing logs to disk. Clean shutdown successful.

reversal crashed due to no enemies alive when choosing a target for his secondary effect