Weapon Infusion: At Andre the Blacksmith, you can infuse weapons with various Gems to alter their scaling properties or add elemental damage. For example, a Heavy Gem increases Strength scaling, while a Sharp Gem increases Dexterity scaling. Crystal adds Intelligence scaling and magic damage, while Lightning adds Faith scaling and lightning damage. Choose infusions that match your build's stats.
Soul Transposition: After defeating the Curse-Rotted Greatwood and obtaining the Transposing Kiln, you can give it to Ludleth of Courland in Firelink Shrine. He can then transpose boss souls into unique weapons, spells, or rings. Each boss soul offers a choice of one or two items, so choose wisely based on your build.