Thunderkyn HO!

Thunder, thunder, thunder, Thunderkyn! Hoooo! A closer look at the exo-frame-wearing, heavy-weapons-wielding, 80s-cartoons-sounding Brokhyr Thunderkyn.

Three engineers who strap themselves into a modified frame meant for doing heavy construction work, then pick up heavy, exotic weaponry... this is how geeks, I mean Brokhyr, go to war!

The Brokhyr Thunderkyn can be taken in units of 3 or 6, and have several uses for a Leages of Votann army.

Brokhyr Thunderkyn are... cheap.

What's the cheapest non-character unit in the Leagues of Votann 10th edition index? A three-man unit of Thunderkyn. Well, technically a unit of Hearthkyn split by a Sagitaur is cheaper, but Thunderkyn are the cheapest without resorting to using special army construction rules on a transport datasheet.

At 95 points, and 9 wounds in the unit, they are also the highest number of wounds per point in the army if we're not looking at characters. (Brokhyr ironmasters actually DO have the highest number of wounds per point, due to their array of assistants.)

It's interresting to note that Thunderkyn cost the same as a Primaris Eradicator squad.

Brokhyr Thunderkyn are... tough

They are Toughness 6, the best we have on any non-vehicle unit, a 3+ save and 3 wounds each. That's basically Gravis armor... Indeed, the defensive statline is exactly the same as Primaris Eradicators. The eradicators have one point better leadership, being the only difference.

While far from invulnerable, it actually takes more shots than you'd think to take down Brokhyr. Cover and Void armor helps against things with good AP.

Brokhyr Thunderkyn are... flexible

When we come to weapons loadout, that's where the similarities to Eradicators stop. We don't have meltaguns. We don't hit as well as them (unless we have tokens) and we don't have built-in rerolls. But we do have some really great guns, and we hit on 5s in overwatch.

Bolt cannons are actually awesome. With range 36" they can threaten a lot of the board without needing to move - if you have any tall ruins in your deployment zone, put them there and rain death. Even without plunging fire, bolt cannons put out strength 6 AP-1 damage 2 shots at a good rate, 2 hits per gun per round on average without tokens (because of sustain 1) - that's 6 hits on average for the whole squad. On overwatch, you do 1.5 hits per gun on average, or 4.5 for the whole squad. Into space marines or other two-wound models, this will hurt even if the AP is not amazing, and strength 6 is enough to ping the odd double wound off anything toughness 11 or less.

You do get bolt cannons on your land fortresses and sagitaurs, however, and those are twin linked which makes them even better at pinging high-toughness wounds, so depending on your list you may not want these guns on your thunderkyn as well.

SP conversion beamers are funky. They are extremely unreliable. If you enjoy big swings, these are for you. They seem to be made for overwatch, having a 24" range (which is max overwatch range) and sustained hits D3. They also have conversion, which means that outside of 12, any hit roll of 4+ will cause a critical hit. But you only have one shot per gun. That means that if you can keep your distance, you do 1.5 hits per gun on average without tokens (4.5 for the squad) or 1 hit per gun on average in overwatch (3 for the squad). So fewer hits than the Bolt cannons on average, and because each gun has a 50/50 chance of doing absolutely nothing, you'll have rounds where these are very underwhelming and other rounds where they wreck things.

For damage, they have strength 7, AP-1 and 3 damage. They seem to be tailored a bit towards killing things like enemy Thunderkyn, Gravis-units and the like, though the AP is low for that. They can also ping vehicles for fairly significant damage sometimes, but low AP means that will also be very swingy.

If your other army is Orks, pick Conversion Beamers. Otherwise probably take another weapon.

Graviton Blast Cannons are also a bit weird, but probably the most interesting choice. They have a range of 18", which means you'll likely either put them in strategic reserves or in a Land Fortress. These guns are good into nearly anything. At D6 Blast shots, you'll score 1.75 hits per gun (5.25 for the unit) into vehicles without tokens, more into most units. In overwatch, 1.17 hits per gun.

After hitting, wounding is interresting as well. As an anti-vehicle 2+ gun, it wounds all vehicles on 2s. At strength 5, it wounds most infantry on 3s or better. AP -2 is great for 10th edition, and at damage 2 you will pick up normal space marines quickly - and deal a good amount of damage to vehicles as well. The only target this gun is not amazing against seems to be heavy infantry like Eradicators (the kind of target that the conversion beamers is best against), and even there the AP-2 means it's not entirely bad.

Based on gut feeling, I'll be going for the Graviton cannons, even though their range sucks.

Math time!

Lets look at some example targets! We'll assume optimal range, and look at the output of a unit of 3 thunderkyn. Goonhammer has kindly identified some of the most common target profiles in 10th edition as part of their datamining series, so we'll lean on that wisdom for our targets. We will add one that I feel is relevant though, the "Gravis equivalent" of 3 men with T6, a 3+ save and 3 wounds.

• Target designation "Guard": 10 man unit (T3, 5+, 1 wound)
• Target designation "Sister": 10 man unit (T3, 3+, 6++, 1 wound)
• Target designation "Marine": 5 man man unit (T4, 3+, 2 wounds)
• Target designation "Terminator": 5 man unit (T5, 2+, 4++, 3 wounds)
• Target designation "Gravis": 3 man unit (T6, 3+, 3 wounds)
• Target designation "Monster": single model (T9, 2+, 4++, 10 wounds, MONSTER) 
• Target designation "War dog": single model (T10, 3+, 5++, 12 wounds, VEHICLE)
• Target designation "Knight": single model (T12, 3+, 22 wounds, VEHICLE)

The math confirms our more informal conclusion: Without range, tokens, cover etc taken into account, the Graviton Cannon is by far the best choice.

A single tokens will actually increase this effect - because Bolt Cannons and especially Conversion Beamers get some of their efficiency from natural 6s to hit (sustained hits), they benefit less from a +1 to hit than the Graviton Cannon does.

A second token is more interresting. In most cases the Graviton Cannon will benefit more than the others, because it has a lower strength. Indeed, neither of the other guns get any benefit at all from the second token against Guard or Sister targets. Against the War dog and Knight targets the situation is the opposite, as the Graviton Cannon can't benefit from a second token due to its Anti-Vehicle 2+ rule. But as we see with the Monster target, the extra AP of the Graviton Cannon means it is still much more efficient than the other options.

Range is the only reason to take anything other than a Graviton Cannon. If you don't mind getting within 18" to shoot, the Graviton is the only choice you should consider. But what if you like more range?

From what we see here, the Bolt Cannon looks superior into most "soft" targets, the advantage of Conversion beamers against hard targets being only marginally better. With better range, the Bolt Cannon seems an obvious choice for our "second best gun".

The reason you might consider Conversion beamers could be overwatch? It would make sense that getting sustained hits on both 5s and 6s in overwatch could help them a lot. Lets calculate: In overwatch against Guard or Sisters (giving Graviton cannons the most bang for their Blast rule), a squad with Bolt Cannons will do 4,5 hits (vs 6 normally, 75% efficiency), a squad with Conversion beamers will do 3 hits (vs 4.5 normally, 67% efficiency). What's going on here? Well, Conversion beamers have sustained hits on 4s as well in normal shooting, so naturally they lose a full third of their efficiency. The bolt cannons are actually helped here by the fact that they are at their best at natural 6s.

For the record, Graviton cannons also simply lose a third of their efficiency. So Bolt cannons gain some efficiency in overwatch compared to the other two guns.

...and remember that we've been working at the Beamers optimal range. The other two weapons don't have to worry about that.

Conclusion

Consider Bolt cannons for range (and overwatch into soft targets), but Graviton cannons are where its at. The beams have to sit the index-times out unless GW makes sweeping changes.

With Bolt cannons or (especially) Graviton Cannons, Thunderkyn are a unit worthy of being included in your list. They are cheap wounds, pretty tough, and are able to deal a lot of damage. And if they get killed, it's one of the cheapest ways you can get a judgement token onto the enemy.