Shield-Captains are often leaders of a Custodian Squad of the Emperor's personal bodyguards. They are not to be confused with the Companion who are the BFF's of Big Daddy G and are much more more limited to 300. The Shield-Captain is much more general in a sense in terms of military engagement. They are the equivalent of the vanilla Space Marine Brother-Captain, but of course in the Custodian's sense of things, the Shield-Captain is several orders of magnitude more powerful and rapetastic than the mentioned former.
Shield-Captains are so named because of the distinctive Stormshields they carry (Although Stormshields can also be carried by more normal Custodian Guards and the Shield-Captain can opt to not carry the shield) which is an ornate, master-crafted shield in shape of the Aquila symbol. They are also distinctive by being mostly helmetless, following the Space Marine tradition of high ranking persons not wearing helmets cause helmets are for pussies. Other than that, Shield-Captains are armed with either the iconic Guardian Spears or Sentinel Blades and Power Knives. Thank the Emperor these guys still wear their power armor.
Shield-Captains are extremely powerful individuals, already more so than the ridiculously tough-to-the-balls Custodian Guards. The basic stats for a Shield-Captain are: BS/S/T at 5, WS at 6, I at 5, A and W at 4, Leaderships of 10, a 2+ Sv and a 5+ Invulnerable save. These monsters of a man can literally bench-press Ork Warbosses like Grots and come equipped with all the standard Custodes weapons which can turn a Grey Knight Paladin into Swiss cheese.
The only downside is that, like the Custodian Guard, the Shield-Captain lack master-crafting and grenades as well as costing as much as a Land Raider.
In 8th Edition
The Shield-Captain remains a powerful, if expensive, beatstick. Statted out as WS 2+ BS 2+ S5 T5 W6 A5 LD9 SV 2+, with the option to take a Misericordia for an additional attack. Swap the standard-issue Guardian Spear with a Sentinel Blade, and you can gain the use of a Storm Shield for extra survivability. Still no grenades, however.
For 190 points, Shield-Captains are the very definition of brutality. It's basically a Praetor with +1 to all his stats save WS and BS, a Guardian spear, a Custodian armor, an Iron Halo and krak/plasma grenades, plus the Legio Custodes, Precision strike/shot, Counter-attack special rules and a nasty selection of various tools of war. Solarite gauntlets and claws, every flavour of spears, Archeotech pistol, digital lasers (yes, 6 Attacks and you can get more from the spears), melta-bombs, Arae-shrikes and teleportation transponders (deep-strike motherfucker!) mean this guy can kill whatever you want, wherever you want. All this is pretty impressive by itself, but if you ever read or heard something about the Legio Custodes in 30k, you know what made this guy hated and reviled by every sane player around.
Yes, you know about the Cheestodes and his infamous cyber-familiar/Praesidium shield combo?
Never heard of it ? Say goodbye to your innocence and your dream of a balanced game you fool. Rerollable 3++ and -1 to Hit you in close combat. No fucking joke, you must avoid using attacks with AP2 or better against him because he will tank them better than stuff with no AP at all (Though if the Custode's player is smart he'll just use the invulnerable save all the time, instead of just for AP1/2 attacks, which is perfectly legal). This sole feature made the Shield-Captain one the toughest bastards in the ENTIRE GAME, because having 6 S6 AP2 attacks which generate additional attacks on 6s to hit and Instant Death on 6s to wound at I6 or 6 S10 AP1 master-crafted I1 attacks didn't make him dreadful enough. But all is not lost yet ! You can still pray for your few Instant Death attacks to insta-kill this obnoxious banana Mary Sue, because at least he doesn't have Eternal Warrior.
Aaaaand here comes the Tribune upgrade. At a price of 25 more points, and if you're taking him in a detachment of 2000 points or more, your Shield-Captain gets Eternal Warrior and Fearless and you can even choose your Warlord Trait for extra shenanigans. Enjoy your Primarch-stomping tactical genius.
Fortunately, FW saw the obvious problems of such amount of cheese and nerfed the bastard down, erasing the cyber-familiar from existence. Now the Shieldtribune "only" gets a 3++ with no re-roll, which is still enough to murder half of the primarchs single-handedly.
|Forces of the Adeptus Custodes|
|Command:||Companions/Hetaeron - Shield-Captain|
|Troops:|| Allarus Custodians - Aquilon Terminator - Custodian Guard |
Custodian Warden - Sagittarum Guard - Sentinel Guard
Vexilus Praetor - Venatari - Warder
|Walkers:|| Contemptor-Galatus Dreadnought - Telemon Heavy Dreadnought |
Venerable Contemptor Dreadnought
|Transports:||Coronus Grav Carrier - Drop Pod - Grav-Rhino - Rhino|
|Vehicles:|| Caladius Grav-Tank - Dawneagle Jetbike - Gyrfalcon Pattern Jetbike |
Pallas Grav-Attack - Venerable Land Raider
|Flyers:||Ares Gunship - Orion Gunship - Stormbird|
|Titans:||Warlord-Sinister Pattern Battle Psi-Titan|
|Auxiliaries:||Sisters of Silence|