Beyond the Wall - Alternative Initiative System for Long-term play

The Beyond the Wall initiative system is elegant and easy, and absolutely perfect for a one-shot, where players can sit in their initiative order and there’s no question of turn order. However, running BtW as a campaign for a year, I found that for long term games you need an extra option so that the order is not always:

Powerful monsters with more hit dice than the PCs > PCs > Low level monsters who are quickly slain.

So, borrowing from AD&D 2nd Edition, here is an alternate initiative system that can be easily added and implemented for long running Beyond the Wall games.

Each turn of initiative a single player rolls a d10, the result of which is added to each PC’s initiative (and to that of any NPC hench, or anyone else fighting on the “PC” side). Likewise, the GM rolls a d10, the result of which is added to the HD of any NPCs or monsters opposing the PCs.

Play proceeds in descending order, from highest to lowest initiative value until all have acted and then the next turn begins with each side rolling a d10. If there is a tie, the PCs are considered to act after the NPC. In the case of PCs with the same initiative, they can choose which goes first each round, giving them some flexibility.

Example: 
Bastian (init 3), Freda (init 2) and Marthe (init 1) are fighting four goblins (HD 1) and a manticore (HD 6).
Marthe’s player rolls for the PCs and gets a 5 on the d10. Each player adds 5 to their PCs initiative and gets: Bastian 8, Marthe 7 and Freda 6.
The GM rolls a d10 and gets a 1, resulting in monster initiatives of: Goblins 2, Manticore 7.

The final initiative order, proceeding from top to bottom becomes:

• Bastian
• Manticore
• Marthe
• Freda
• Goblins

This round Bastian is lucky enough to act before the Manticore, but he may not be as lucky on subsequent rounds. But, unlike the basic fixed initiative rules from the book, with these rules the PCs have a chance to act before the Manticore if they roll well on initiative.