If Fiora Peerless has Svellsongur attached and is attacking or defending alone, does her might effectively quadruple or just double?

Ruling: Fiora's might would quadruple. Both doubling triggers enter the chain and resolve one after another.

Sequence:

• Fiora starts at base 3 might
• First doubling effect resolves, bringing her to 6 might
• Second doubling effect resolves, bringing her to 12 might