Space marine heavy armour

Hi guys. My main opponent just built a new space marine army with two tac squads, THSS terminators, a thunder fire canon, land raider, rhino, librarian and deredeo dreadnought from forgeworld.

We've played one game so far and it was a draw due to objectives, but very boring. He castled up in the corner and anything I tried to move into range was shot down by the longer range and more powerful guns of the space marines.

The deredeo was particularly nasty. It's an armour 14 dreadnought with 4 twin linked autocannon shots, two heavy bolters and some missiles that I can't remember the stats of. It can also gain skyfire if it doesn't move that turn.

I was wondering if anyone had any ideas of how to tackle that kind of armour and fire power. I'm pretty new to playing Dark Eldar. Just hit 1500 points and using models I've collected to paint. There are wyches in my army, so I'm open to any changes and suggestions.

Thanks

MSU would seem to be the best option here. Flood the table with targets. He can only shoot down a few each turn.

Oh and the Deredeo is AV13, not 14 by the way.

MSU, lots of Dark Lances. It sounds like a Reaper would not go amiss here, either.

Maybe try several void raven or razor wing and cover him in large blasts?

And many many small units.

Yea. Voidraven would certainy be an option. Overwhelming CC could probably work too. Lolz for WWP Archon with Scytheguard. Freakshow with concussive blasts from Reapers or corsair prince's skyburst.

MSU with some cheapycheap incubi units with Klaivexes would threaten them termies so much that they would have to shoot them first while you keep your shooting power intact.

This army has fewer but more powerful shots so it should struggle with hordes approach too. Army composed of hellions, bikes, scouges and beasts in large numbers, followed by wyches as second wave with hwg hekatrixes should do fine too. Assault T2, drown them in attacks whilst attrition works against him due to PFP.

EDIT: I faced a similarly tough FW salamanders army with LR Achilles and their unique HQ Dread few times and it is doable with standard shooty list IMO. The key IMO is focus on units that you CAN hurt easiest and what would ease up the pressure on your boyz.

He had 2 tac squads but only 1 rhino?   That's some dedication to castling.

To me haywire is the only effective way to deal with heavy armor.  Although lances are slightly better at glancing/penetrating av14 than las cannons, I've never really found lascannons effective against land raiders to begin with.

As mentioned above this may be the very rare exception where a voidraven is worth while, especially if you go with dark scythes on top of the bomb.  A Grot drop or two might go a long way to reducing how much fire that dread puts out.  Stick an aberration with scissorhands in there and he may even glance it to death while tying it up.

IMO you're lucky he's playing marines in the more traditional way.   When I play as marines it's scout MSUs supported by 3 stalkers, devastators, and skimmers/flyers as needed.  There really isn't anything effective a dark eldar player can do against it without allies or spamming grot bombs (of course that's kind of true regardless isn't it?).

This style can even castle well by spreading out cheap vehicle formations over a larger area and the scout transports rule which doubles the opponents deep strike scatter.

Oh ya and if you thought the 4 shot dread was bad... pray he never finds out about stalkers.

2 or more squads of jetbikes could put pressure on his castled position.

Though I don't have one, a voidraven sounds like the best option, the best type of anti-vehicle from my looks at the codex is the heat lances, and darklight. Maybe some ravagers and the voidraven, the void lance is higher than the dark lance, but not by much, unloading missiles or bombs on a dug in position though would really make him second guess piling his units in a single area. I do feel your pain though, forgeworld, I sorta dislike it when people field things like that, something so overwhelmingly strong that shouldn't be really used in a casual game, but I digress, fast attack units with anti infantry would also be good, give him the choice of which of your units are priority, some scourge or venoms could throw him off, while your heavy firepower picks away at the dreadnought, either way though, that is a very rough circumstance.