How to increase weapon strength with the player

Question

I've got a player who's character has a home-brew weapon that's supposed to grow in strength alongside the character so it can be used through the whole campaign.

I get that, normally, throughout the campaign, characters would swap their current equipment with better alternatives and also enchant their weapons to keep them relevant in stronger encounters, but I'm trying to accommodate for that in just one weapon, so that there's no need to switch if the player doesn't want to. That and the lore behind this particular weapon reflects the growth in strength alongside the player since, once acquired, it's supposed to become this particular character's permanent primary weapon.

I've considered using a level system similar to players' to increase damage, and grant effects as it grows, but I don't know if that's the best option, or what to do in order to achieve the desired effect.

The weapon is based off and started out as a standard short-sword, but since it's magic (and legendary), we've already applied the standard +1 from masterwork.

Thankfully it hasn't come up yet, so I have a little time to iron this out, but it's bound to be needed soon.

Are there any official rules that allow for improving weapons instead of replacing them?

Answer 1

Give them a Scaling Magic Weapon

Pathfinder already has a system for magic items that grow with the user's level called Scaling Items.

Typically, player characters find themselves buying and selling magic items as they gain levels to keep up with the increasing threats they face. Items come and go from each character’s inventory with such frequency that they hardly have the chance to impact the game’s story. Scaling items, however, increase in power along with the characters who carry them, allowing an old and cherished item to develop and retain its utility rather than being sold and forgotten.

They're specifically designed to avoid having the player constantly sell the items in that category and swap them out for a new one, which accomplishes what you want.

There are a couple things to note however:

• Due to how pricing works for scaling magic items, it often results in a magic item with a cost far above what it's current value to the player is (which may result in them just wanting to sell it). As a gm I've dealt with this by allowing players to sell it for a price equivalent to the abilities they've unlocked already.
• You need to work with your player to design a weapon that suits them. The examples are good and all, but you shouldn't just flat out use them, since it may differ from a player's intended build or playstyle. Instead, use them as inspiration for finding a weapon that works for your player, that they won't just want to sell.

Answer 2

Just say that's what they're doing narratively, while using the normal system

There's no need to have the mechanical system where you can trade out an item for another one narratively correspond to selling an item. If a player would like to have a consistent weapon for lore reasons, the benefits and drawbacks to that fact, independent of the wealth mechanics, are approximately balanced. Consequently, letting them have that while using the normal system for weapon growth won't cause any mechanical problems.

Note that this will only come up if a player wants to remove an enchantment from a weapon or change what kind of weapon it is in a way that transformative doesn't solve. Players frequently, in my experience, don't swap out weapons as they level up, instead planning out their weapon enchantments ahead of time so that they don't have to lose money by selling their current weapons. I typically don't enforce WBL, though, so that is probably at least part of why my players are hesitant to sell expensive items (since the lost value will not be magically replaced by an equal amount of fully fungible future treasure).

If it does come up, though, letting a player 'abandon everything they know and start over' (losing their current weapon enchantments but narratively keeping the same weapon) or 'disenchant' their weapon (losing any number of specific weapon enchantments) isn't actually a problem. I'd make sure not to give this player an extra-lenient gear-changing system while being extra harsh on another player at the same time, but ultimately this is something they should be able to do without GM buy-in and making it easier for them isn't going to significantly change your game in any negative way; it just helps them avoid trap options or makes the penalty for falling into one less harsh, depending on your house rules.

Answer 3

Pathfinder has many options for giving a player an weapon that becomes stronger as they do or ways to grant that flavor.

I rank these options starting with the one that takes the least amount of work for you.

1. Allow players to upgrade their equipment

You could allow players to upgrade equipment by having them pay the difference in price -- so upgrading a +1 weapon to a +2 weapon requires paying 6,000 gp. This eschews all the extra annoyance of having item creation feats or paying an NPC to do it.

This is such a common house rule that even the official organized play program (Pathfinder Society) uses this method.

Your player could reflavor this process by having the PC spend gold on reagents for a ceremony that properly attunes the weapon to his current power.

2. Use an archetype with a scaling weapon

A number of archetypes and player options grant a PC a weapon that scales with level. Examples of these include:

• Bladebound Magus, a melee combat spellcaster that gains a sentient weapon that grows in power
• Blade Adept, an arcanist that has the bladebound magus's weapon
• Jistkan Artificer, a melee combat spellcaster with a golem arm that gets stronger with levels
• Gloomblade, a fighter that has a shapeshifting shadow weapon that gets more powerful with levels
• Phantom Blade, an occult spellcaster with a ghostly weapon

A number of 3rd party options like Dreamscarred Press's soul knife would also fit the flavor.

3. Grant a scaling magic weapon

Pathfinder Unchained introduces the Scaling Item optional rules. These rules allow a PC to have a magic item that increases in price and power as the character level increases. This comes at the cost of less wealth for the PC, so you would have to give this PC less gold.

You can use one of the sample weapons from the book or you could create the weapon yourself with the below recommendations.

According to Table 4-13: Value of Scaling Items, a magic weapon would be a "wonder" that accounts for 30% of the character's wealth. With this, we can estimate the weapon will scale accordingly:

• At 2nd level, the item becomes a masterwork weapon
• At 4th level, the item becomes a +1 weapon
• Between 7th and 8th level, the item becomes a +2 weapon
• At 10th level, the item becomes a +3 weapon
• At 12th level, the item becomes a +4 weapon
• At 14th level, the item becomes a +5 weapon
• At 15th level, the item costs as much as a +6 weapon
• At 16th level, the item costs as much as a +7 weapon
• At 17th level, the item costs as much as a +8 weapon
• At 18th level, the item costs as much as a +9 weapon
• At 19th level, the item costs as much as a +10 weapon

Note that a weapon's enhancement bonus generally cannot go higher than a +5. So it would need additional abilities if the weapon's total price is greater than that of a +5 weapon.

4. Use Automatic Bonus Progression

This is the "nuclear" option. Pathfinder Unchained's Automatic Bonus Progression eschews bonus-granting magic items entirely in favor of automatically granting the bonuses to the PCs. This comes at the cost of reducing wealth by level.

Though meant to apply to the entire party, you could possibly apply the weapon attunement ability to the specific PC at the cost of about 25% of his wealth.

Weapon Attunement

The character can attune herself to any one weapon in her possession, and can change that attunement once per day. The attuned weapon gains a +1 enhancement bonus at 4th level. At 8th level, the character can split her attunement between two weapons, granting each a +1 enhancement bonus. At 9th level, she can grant a single weapon a +2 enhancement bonus instead of granting two weapons a +1 enhancement bonus each. At 14th level, she can either grant a single weapon a +3 enhancement bonus or grant two weapons a +2 enhancement bonus each. At 15th level, she can either grant a single weapon a +4 enhancement bonus or grant two weapons a +3 enhancement bonus each. At 17th level, she can either grant a single weapon a +5 enhancement bonus or grant one weapon a +4 enhancement bonus and another weapon a +3 enhancement bonus.

If you use Automatic Bonus Progression, I recommend treating the PCs as 1 level higher (so a 2nd level PC gets the 3rd level benefits). As someone who uses this optional rule in his home game, I've found the basic progression to be too slow and have PCs end up with bonuses too low for their level. Level + 1 feels about right.