Griffon Heavy Mortar Carrier
At first glance, the Griffon seems to fall in a strange "in-between" zone -- the heavy mortar is too large to be man-portable, but it isn't large enough to achieve the same range or firepower as its larger cousins. Mounting it in a Chimera chassis almost seems a waste of both, so many regiments that are not specifically dedicated to artillery don't bother replacing Griffons as they are lost (and wish they had once they hit the next fight).
However, it is precisely the relatively light weight of the heavy mortar that gives the Griffon certain advantages over the other artillery pieces. Because the shells are smaller, the cannon is easier to reload and can achieve higher rates of fire. Because the Chimera is so much heavier than its cannon, the recoil is not as severe, allowing the Griffon to precisely drop shells on target. While it lacks the destructive potential to crack open a fortress or destroy a siege tank, it is more than a match for infantry and light vehicles, and so it can focus on destroying the enemies lighter, more mobile elements and leave the Earthshakers free to engage the harder targets.
- The default (and so far only known) pattern of Griffon doesn't have a tall, curved gunshield like the Basilisk or Medusa. Even though Vanaheim also makes angular variant gunshields for those other artillery pieces, the Griffon gunshield is much lower and more angled inward than the others. Presumably, other patterns with fully enclosed turrets or taller gun shields exist.
The Griffon's heavy mortar isn't especially powerful at only S6 AP -1, especially for a vehicle-mounted mortar, but it ignores cover and line of sight entirely and keeps a respectable 48" range. Its main competition is the Wyvern; the Wyvern rerolls wounds, but doesn't ignore cover like the Griffon. Both are pretty much optimized for GEQ targets, but the Guard already has a lot of tools to do this; therefore it's debatable whether the Griffon still has a niche. Aside from that, it's a Chimera chassis with the performance you'd expect out of one.
While the Griffon was occasionally seen in Guard armies in earlier editions of 40k, as of 8th/9th edition the GW model kit is long discontinued and the Forge World version is no longer available either. As such the Griffon is now considered a Legends entry.