A party member in a D&D 5e game I'm in is playing a halfling paladin. It occurred to me (for whatever reason) to ask what weapon they were wielding, and they said their main weapon was a maul, and their backup was a warhammer/shield combo).
Upon checking the Weapons table, I discovered that mauls have the "Heavy" weapon property:
Heavy. Small creatures have disadvantage on attack rolls with heavy weapons. A heavy weapon’s size and bulk make it too large for a Small creature to use effectively.
The player seemed to be unaware of this (a similar character in Critical Role apparently wielded heavy weapons without issue – of course, CR is not necessarily a perfect demonstration of the rules as written).
As such, I was curious whether there is anything in the rules (i.e. not homebrew or a house rule) that cancels out this innate disadvantage for player characters, other than gaining advantage from some other source in combat.
(Note: the issue has already been resolved in our game between the player and DM, so it's purely a rules question.)
Best Answer
A potion of growth or an enlargement spell
By changing to medium size, temporarily, that disadvantage will go away. Both the potion and the spell make that possible.
Comment: this point got some discussion early in this edition's release. (This question is related but not identical, as is this one). This little piece of verisimilitude -- which parallels a similar rule about weapons for Large and Huge creatures not getting a damage increase if a medium sized creature uses it (DMG p. 278)-- avoids the absurdity of a halfling wielding a greatsword, while still allowing for a variety of other absurdities.
FWIW, this small sized character can ride a medium sized creature. Gnome and halfling Rangers (for example) can take good advantage of that if they are Beast Masters.
In the interest of Rules as Fun (RAF1)
In making a ruling that is not strictly RAW, consider what is behind the character build, and the use it is making use of Small size. As the DM, consider the impact of ruling that the character counts as Medium for all rules purposes, such that the bulky paladin armor makes up the difference. In that case, a maul-wielding halfling might provide a bit of light comedy, but it would have very little impact on game balance. It's only if the player expected to get all of the benefits of Small and yet avoid any negative consequences of that size that the character concept begins to border on "cheesy" as well as funny. (Thanks to @NeilSlater for this point)
1RAF