How powerful is this stat block?

[KAmber]

I'm trying to construct an encounter with a powerful tactician, who I want them to realize they can't beat, but I'm concerned that I'm going to pit my party of four level 3 players against a force that will crush them too fast. He's a very weak character on his own but provides many benefits to his allies. He's going to have three or four bandits(srd) as his henchmen for this encounter and I'm kinda concerned.

Giornio Vaticus
Str 10 (0) Dex 15 (2) Con 13 (1) Int 18 (4) Wis 15 (2) Cha 14 (2)

Hit points 26/26 (6d6+6)
Armor class 15
Speed 30ft
Saving Throws Int, Wis, Cha +3
Skills Arcana, History, Religion +3, Intimidation, Persuasion, Deception +6

Senses passive Perception 13

Fight For Me.
If Giorno is within 60ft of them, Giornio’s allies can use a reaction to add 1d4 to saving throws and AC for the rest of the turn if he hasn’t been hurt in at least 2 rounds.
But Not With Me.
If Giornio is within 60ft of them, Giorno’s allies get a bonus d4 to damage rolls if he hasn’t attacked in at least 2 rounds.
Can’t Hurt a Fly.
If Giornio doesn’t have any allies within 60 ft. and he doesn’t obviously pose a threat, Giornio can roll Deception(if he is actually dangerous) or Persuasion(if he really is unarmed and unable to attack and stuff) against opponents’ passive Insight. Anyone who he succeeds against can’t kill or give him a serious wound, but they can apprehend him, cause nonlethal damage, etc.
If Giornio attacks someone while they are under the influence of this ability, the effect is broken and he can’t use this ability against them again for a significant amount of time.

ACTIONS

Keep Up the Good Work.
Up to three allies within 60 ft. get 2d4+4 temporary hit points and +1 to attack rolls and save DCs.
Keep Up the Good Work can’t be used on the same allies until Giornio takes a short rest.
Defend Me!
Up to three allies within 40 feet can use their reaction to move up to their speed towards him and take up a defensive position, not provoking opportunity attacks. While they stay within 10 feet of him, he gets a cumulative +1 to AC and saving throws. (Max 3.)
Giornio can only have a maximum of three allies defending him at a time.
Like That, Fool.
Giornio grants advantage to an ally within 60 ft. on their next attack roll or skill check.
Retreat!
Giornio and each ally within 30 ft. immediately move up to their speed. For the next 10 minutes, they can use the Dash, Disengage, or Hide action as a bonus action. Any allies that make attacks while under the effects of Retreat! lose the benefit.
Unarmed attack. Melee Weapon Attack: +3 to hit. Range 5 ft. Hit: 1 bludgeoning damage.

REACTIONS

Defend Me Better.
Giornio can force someone reroll an attack roll against him. This can only happen if an ally is in a defensive position. (See Defend Me!)

[Onos]

As you've noted, Giornio is fairly weak and almost none of his abilities directly affect him. What you'll want to do is apply his effects to the Bandits and recalculate their CR based on new HP, Attack Bonus etc. For **Defend Me Better** are you meaning for it to be once per turn or Disadvantage?

And I assume Giornio is a Small creature going by his HD? You may want to bear that in mind if your group has a wrestling enthusiast or anything, he may get rushed and grappled.

This looks really cool btw, how are you planning on showing the "can't be beaten" part? It's always risky in case the PCs decide to slug it out but I could see this with a nice terrain setup working well. Perhaps allow the party to demolish a few Bandits then have Giornio step in and start directing them?