How merging works in Steal an Anime Pack

The game description says you can merge your packs. The wiki splits that into two machines. The Merge Machine takes two copies of the same pack and returns one heavier pack, which hatches a heavier unit. Path Packs cannot be merged. The Mutation Machine takes three copies of the same unit that have no mutation yet and returns one mutated unit. I do not have a formula for how the two pack weights are combined, so that cell stays empty.

Mutations

Five mutations, from the wiki: Golden x3 (1 in 60), Emerald x4.5 (1 in 150), Diamond x6 (1 in 300), Cursed x8 (1 in 600), Transcendent x10 (1 in 1,200). The average cash multiplier of a mutated unit is listed as x3.67. Every 45 minutes an event can double one mutation's odds. Golden events are listed as 42% of those events. A code for 2x Mutation, when one is active, is on the codes page.

Weight and size

Income scales with weight: 1 kg is x0.9, 60 kg is x1.72, 1,000 kg is x13.45, and 100,000 kg is x268.45. Past 1,000 kg the curve flattens. There are 13 size names from Tiny to Godly. Sakura's Domain, Grand Blue and Monarch Empire use a standard size table (Godly 1 in 10,001). Snowy Zone through Eternals Kingdom use a Huge+ table (Godly 1 in 5,601). On open, a pack can also roll a weight bonus: 1.5% for x1.15–1.75, 0.3% for x1.75–3, 0.03% for x4–12.

Grade and trait

Grade runs from D at x1.1 to Ω at x250 across 12 steps. Each roll costs 1 gem. A random grade averages x1.54. Traits are 16 kinds, from Nature at x1.2 to Blessed at x3, and a random trait averages x1.22. The wiki multiplies size × mutation × grade × trait. Gems also drop from a tower in each area.

The wiki adds one sentence about limited units: only a mutation from the Mutate Machine counts toward income. It does not spell out the rest, so I am leaving that rule as that one sentence. Which pack is worth merging first depends on the route on best packs and on the base income on units.