The direct answer
Build around a small number of effects that reinforce each other. A clear damage engine plus one defensive layer is usually stronger than collecting unrelated bonuses because each appeared at a higher tier.
Emblem levels and Charm availability are separate questions: one controls how an upgrade scales, while the other controls what the campaign shop or reward pool can offer.
How to compare options
Start with the upgrade family and type. Then open its linked level pages to see which values actually change at each level.
Check whether an effect stacks and whether it has a stack cap. Repeated copies are poor value when the effect is capped or does not stack.
For shop entries, compare price, currency, tier, pool, drop chance, and the effect type together.
Follow Requires hero, Requires upgrade, Related upgrade, and Applies status links before committing to a synergy.
Cutthroat’s Blade was added to the Common Charm pool in version 0.8.57278 and grants critical-hit chance on Finishers.
Price changes to remember
Version 0.8.57278 reduced Wallace’s Flamberge sword cost to 3 Dragonstones and set the Celtic Longsword price to 500 Triskelle. Use the patch page when static values and current live balance differ.