Can someone explain the Exogalactic Strikeforce in Fallen Spire?

[carldong]

Try replacing it with a Mil 3 then, if you have the K available.

No K is actually my real issue now. Now I decide to give my Spire fleet a try and kill that first AI's homeworld that basically blocks my path.

Building Warheads now... Watch for it, dam AI!

Not sure if it is a good plan. I decide to first ram down everything in the Core world (Transports + Mini Rams to assassinate them), silently pass my Cloaker Starships (I only get MkI) with Ltn Warheads, Armored Warheads, and Spirecraft Martyrs through wormhole with a whole bunch of Scouts and Scout Starships, and probably some SC Shield Bearers, and hopefully if I understand correctly, cloaking boosters should keep them alive as long as possible. Then Armor down the guard posts, blow up strategic reserve and/or SF as much as I can, send through my regular fleet and starship fleet in transports, Fallen Spire fleet with GalEx one-way delivery system (i.e Jumpships) and/or several SC Penetrators and one shot the rest of the guard posts and hopefully the AI Home Command Station.

There are certain question though. Does Martyrs target buildings? I tested in another game and it seems that I cannot target Command Stations with it, and doesn't damage it when it explodes. I am not worried about "limited numbers" of them because I have so many asteroids in my empire that all I worry about is their energy consumption.

No nukes, of course. I am still going after the FS campaign after killing this roadblock, and I want any K and resources from any planets I take. I hope the AIP from 8 guard posts + Home CS + 100AIP won't push the difficulty too far.

Looks like it is not enough to tech up the AI to MkIII. So still there is hope

[carldong]

I heard that Exos are immune to Grav unless leading ship is destroyed. Is that true?

[Toranth]

I heard that Exos are immune to Grav unless leading ship is destroyed. Is that true?

Not exactly.  The lead ship sets the speed for all other units in that Exowave - every other unit gets a speed of the lead unit's speed + 5.  When the lead unit is a unit, like a Golem or Spirecraft, that is immune to Gravity effects, then all the other units in the Exowave gain the same benefit.  If the lead unit is killed, the other units become free threat, and are impacted by gravity speed reductions as normal.

[carldong]

I heard that Exos are immune to Grav unless leading ship is destroyed. Is that true?

Not exactly.  The lead ship sets the speed for all other units in that Exowave - every other unit gets a speed of the lead unit's speed + 5.  When the lead unit is a unit, like a Golem or Spirecraft, that is immune to Gravity effects, then all the other units in the Exowave gain the same benefit.  If the lead unit is killed, the other units become free threat, and are impacted by gravity speed reductions as normal.

So I would like to snipe the lead first. However, it just mixes up inside the fleetball (or more accurately, fleetline), and I can't find it. Although it is usually the first one to hit Minefields

[Toranth]

I heard that Exos are immune to Grav unless leading ship is destroyed. Is that true?

Not exactly.  The lead ship sets the speed for all other units in that Exowave - every other unit gets a speed of the lead unit's speed + 5.  When the lead unit is a unit, like a Golem or Spirecraft, that is immune to Gravity effects, then all the other units in the Exowave gain the same benefit.  If the lead unit is killed, the other units become free threat, and are impacted by gravity speed reductions as normal.

So I would like to snipe the lead first. However, it just mixes up inside the fleetball (or more accurately, fleetline), and I can't find it. Although it is usually the first one to hit Minefields

The lead ship will always be the biggest, nastiest ship in the Exowave.  The Golem, highest mark Spirecraft or Hunter/Killer, or Mothership will be the leader in those cases.
There's an article here about how Exowaves work in general, and that article links to a Spoiler-heavy Fallen Spire page that discusses exactly how ships are chosen for an Exowave.
The articles are old, but I believe they are still accurate.