I would recommend doing everything you can to upgrade those pets to at least app 4, adept 1 if possible. As a conjuror I use my lvl 24 pet spell while solo or in groups I don't trust cause it can tank (its adept 3) I have also got the adept 2 freebie lvl 30 fire pet which seems to dish out great DPS, but dies in about 3 hits.
I just recently got the spell Aery Rider and managed to upgrade it to adept 1. I have yet to really understand all it is capable of though. It seems to me it is a scout pet with medium damage output and medium tanking abilites.
Anyways in your case if the tellurian recruit is still even con Id say it is your best pet since you have adept 3 of it. I don't know anything about necro pets, but I imagine you get them at the same level as a conjuror and more then likly they are the same type (as in caster, tank, etc). I would guess at lvl 24 you got a new pet spell, that is the one that is meant to replace your lvl 10 tank pet. If you got a level 20 pet it is probably a caster pet, that is the one Id use if your in a group with a trustworthy tank. Don't know if it helps much, but I found most of my conjuror pets on the Freeport Market. Seems like evil spells drop alot on the Qeynos Side, if you have a hard time finding upgrades you might check that. More often then enough I can find Adept 1 spells cheaper then app 3 and 4. People are wanting 2 and 3 gold for app 4 lvl 30+ spells, but I found some of the adept 1's for less then 2 gold.
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Hi