To preface I’m new to hearthstone. I’ve attempted Thrall vs Deathwing in the Book of Heroes over 10-15 times and I’ve come to the conclusion that the fight is bugged.
I don’t know if this is a bug or intended, but from all the content on the fight I can find online, you’re supposed to draw the Alexstrasza card on turn one, but I only draw it on turn 2. This makes the fight seemingly impossible. Ultraxion’s damage scaling mechanic makes the one turn difference insurmountable.
If this is intended does anyone have any tips on what to do?
Ive beated all the recent solo content it is beatable cant remember how i beat him but you can look on online how some ppl beat these dificult heroes:)
I am going to be with some puzzles i looked on youtube 
From what I can read online the fight is meant to be scripted in such a way that you are meant to draw Alexstraza on Turn 1, but a bug causes her to only be drawn on turn 2. These destroys the balance of the fight since you can’t get ahead on the first minion and Deathwing’s hero power eradicates any board you try to build.
New and returning players will quickly give up on this. Yo can’t even switch stories without retiring the entire Thrall campaign. If there is a dev watching, please get on this. This is one of the few things a new or returning player can do to quickly build up a library.
I have the same issue. I draw Alex on turn 2 if even then.
Having the same issue as the original poster
I’ve tried this encounter about 25 times now (conceding most of them after I realized there was an issue) only on 2 of these attempts have I managed to pull Alexstrasza turn 1. For whatever reason it seems like the first card drawn for both me and Deathwing is random which is obviously not intended and completely breaks the entire fight. This has turned an encounter which was clearly already tightly designed into outright impossible.
I’ve been enjoying the book of heroes so far and was clearing them one by one to help build up my collection after coming back to the game. Unfortunately it looks like I’ll have to step away from it until this game breaking bug is resolved.
Can confirm that the fight is still winnable even with drawing Alexstrasza turn 2. Mulliganed the 2nd and 3rd card of starting hand, first random draw for me was the 1 drop 1/3. Deatwing’s first random draw was a 0 mana 6/6 taunt which he played turn 1. Key part was killing my own character with rockbiter/doomhammer to control my own HP resets, and playing each of the legendary dragons further to the left than the previous. The Damage of the first dragon was fairly high before I killed him, up to 12 or 14. As soon as deathwing became vulnerable he stopped doing anything of relevance. Just kept playing 1 creature and hero powering. Not sure if this was because of the scripting being messed up or if the fight is just designed that way. Extremely easy if you can just manage to get through the start of the fight and abuse nozdormu windfury.
After u learn when u should destroy Thrall Its piece of cake.
i recently started book of heroes and started playing HS about 4-5 months ago.
I was stuck on this as well, since the videos out there show a different card draw order.
When i read the comments here about killing your character at the right time, i slapped myself in the forehead and did it in one try lol.
I post this in case any recent players need this too.