ok sold. Included these two. Anything else to tweak or can the stats be locked in...(before a description review..)
The
Armor Class should either be 13 or have a (qualifier) of some kind after the 14 such as 14 (natural armor), since the DEX bonus only accounts for 3 points of AC.
The Challenge is too low at 1/4. According to the CR Calculator it's about
Challenge 1/2 with AC 13 and the current actions.
The
Blood drain has a stray stirge in it:
Blood Drain. Melee Weapon Attack: +5 to hit, reach 5 ft., one creature. Hit: 6 (1d6 + 3) piercing damage, and the giant tabanid attaches to the target. While attached, it doesn't attack. Instead, at the start of each of the giant tabanid's turns, the target loses 6 (1d6 + 3) hit points due to blood loss.
The giant tabanid can detach itself by spending 5 feet of its movement. It does so after it drains 10 hit points of blood from the target or the target dies. A creature, including the target, can use its action to detach the stirge.
I think the above could do with some tweaking. For a start, a giant horsefly is a good deal bigger than a stirge so would presumably need more blood to satisfy its thirst. Stirges may be bloodbags but they're the size of a largish bird like a raven, while the tabanid is as big as a horse. Maybe 20, 30 or even 40 hit points?
The damage seems a bit piddly too. It's only a point higher than a stirge.
Also, maybe have some kind of check to remove the tabanid rather than it automatically succeeding?
Perhaps:
Blood Drain. Melee Weapon Attack: +5 to hit, reach 5 ft., one creature. Hit: 10 (2d6 + 3) piercing damage, and the giant tabanid attaches to the target. While attached, it doesn't attack. Instead, at the start of each of the giant tabanid's turns, the target loses 10 (2d6 + 3) hit points due to blood loss.
The giant tabanid can detach itself by spending 5 feet of its movement. It does so after it drains 30 hit points of blood from the target or the target dies. A creature, including the target, can use its action to detach the giant tabanid by succeeding on a DC 13 Strength check.
That'd make it
Challenge 1 though.
If you want to keep it at CR 1/4 you need to make it more fragile and less lethal by reducing the number of HD and STR. According to the CR Calculator an AC 13, HP 22 (3d10+6), STR 15 (+2) giant tabanid that does 5 (1d6 + 2) with
Blood Drain would be
Challenge 1/4.
I'm thinking that its ability to use Dodging Flight should be prevented or diminished if it's got a rider or is using Blood Drain.
I've just noticed that Dodging Flight and Evasive Flight should use periods rather than colons.
How's this:
Evasive Flight. A giant tabanid gains advantage on Dexterity saving throws when flying and attackers have disadvantage on attack rolls against it.
If the giant tabanid is mounted, it must make a DC 12 STR check to use evasive flight each time it is attacked.
Reactions
Dodging Flight. If a creature of at least Small size attempts a melee attack against a giant tabanid, or the fly is targeted by ranged weapon of similar size such as a giant-hurled boulder, the giant tabanid can try to dodge out of the way as a reaction. The giant tabanid makes a Dexterity saving throw with advantage (it loses this advantage when mounted or using Blood Drain). If the saving throw beats the attack roll or DC of the attack the giant tabanid takes no damage and flies up to 30 feet.
If a giant tabanid is using Blood Drain and successfully uses Dodging Flight it automatically detaches itself from its victim before flying away.
I wondered about restricting the
Evasive Flight's disadvantage on attack rolls to ranged attacks, but I'm not sure about that.