Ok, heres my suggestion:
Make the golden knight be a *|2 creature with text:
"Immaterial.
Golden Knight's attack is equal to the number of Golden Knights on your side."
The immaterial is there to prevent fractal abuse, while the other ability (attack version of swarm) is to allow the damage to ramp up quickly.
In most cases this ends up becoming OP very easily, but considering how difficult it is to get this card rolling it might work out here.
The total damage dealt by using n palaces each turn for t turns will scale as:
(n*t)^3 / 3 + (n*t)^2 / 2 + (n*t) / 6
or:
1 palace
turn | damage this turn | total damage over all turns |
1 | 1 | 1 |
2 | 4 | 5 |
3 | 9 | 14 |
4 | 16 | 30 |
5 | 25 | 55 |
6 | 36 | 91 |
7 | 49 | 140 |
8 | 64 | 204 |
The average game with good unupgraded decks lasts around 8 to 10 turns... with upgraded decks that drops to about 7 to 9 turns.
it takes 5 turns to get your first knight out though, so you only get 3 turns worth with the unupgraded or 2 with upgraded... it may be good to drop the delay on the map a bit or just remove it and add a delay to the Temple / Fort.
The spoiler below shows the scaling if you get n Temples / Forts going at the same time.
Spoiler for additional tables:
2 palaces
turn | damage this turn | total damage over all turns |
1 | 4 | 4 |
2 | 16 | 20 |
3 | 36 | 56 |
4 | 64 | 120 |
5 | 100 | 220 |
6 | 144 | 364 |
7 | 196 | 560 |
8 | 256 | 816 |
3 palaces
turn | damage this turn | total damage over all turns |
1 | 9 | 9 |
2 | 36 | 45 |
3 | 81 | 126 |
4 | 144 | 270 |
5 | 225 | 495 |
6 | 324 | 819 |
7 | 441 | 1260 |
8 | 529 (capped at 23 knights) | 1789 |
4 palaces
turn | damage this turn | total damage over all turns |
1 | 16 | 16 |
2 | 64 | 80 |
3 | 144 | 224 |
4 | 256 | 480 |
5 | 400 | 880 |
6 | 529 (capped at 23 knights) | 1409 |
5 palaces
turn | damage this turn | total damage over all turns |
1 | 25 | 25 |
2 | 100 | 125 |
3 | 225 | 350 |
4 | 400 | 750 |
5 | 529 (capped at 23 knights) | 1279 |
6 palaces
turn | damage this turn | total damage over all turns |
1 | 36 | 25 |
2 | 144 | 125 |
3 | 324 | 350 |
4 | 529 (capped at 23 knights) | 879 |
With 4 plus this scales insanely fast, but getting that many out and function over the span of an average game may be tricky.
Also, it would encourage use of shields such as fire buckler, spines, and skull shield since they would be the only really effective means of killing knights... although other shields would definitely help as well.