Travelers of the Multiverse Unearthed Arcana lists the Thri-kreen race, and its type is monstrosity. I am wondering what playing as a monstrosity would entail.
All things that come to my mind are benefits: not being a valid target for many spells like charm person or hold person etc., but for the life of me I cannot see any mechanical drawbacks, as many class features list 'Creatures' and 'Allies' so I see this as an overall buff.
I am wondering if I should let one of my players play as one. What are the advantages that I did not see, or what are disadvantages (if any exist) of playing as a monstrosity type PC?
Best Answer
There are no real mechanical drawbacks to the Monstrosity creature type.
You are correct that there are practically no effects in D&D5e that effect a Monstrosity differently than it would a Humanoid, unlike Undead or Constructs which can often not be targeted by healing spells. On the other hand, there are various negative effects that can target only Humanoids but not Monstrosities. Mechanically there are thus no real drawbacks to playing as a Monstrosity.
Whether or not there are social consequences within your world is up to you, although I would avoid them. They are generally not fun and only become more tedious and annoying over time. Although the Monstrosity creature type is beneficial, it is a rather situational buff and should not warrant any made-up drawbacks.
The Thri-Kreen race overall is on the strong side, but mostly because of their incredible telepathic communication. A base AC of 13 + Dex when not wearing armor is also very helpful for certain classes (sorcerer and wizard come to mind), being able to stay conscious during long rests is always of use, and their secondary arms allow for more flexibility when it comes to wearing a shield and still being able to carry more than one weapon for two-weapon fighting. So the race has a lot going for it, but nothing that I would consider gamebreaking (least of all the Monstrosity creature type).