Sorry if the post was too old , but just to highlight points :
I would say if you mean
Melkor in his prime form and before even the war against the other's
valar , and before he changed into the darkness before leaving the light
Melkor would crash , smash , and kick
Tulkas nor even him alone but with some of valar and by himself alone and without the need of
maiar and here are things to mention
Tulkas was powerless when ungoliant insnares Tulkas in net and confused Orome and didn't see anything , and he was beating the air in vain and grow powerless and hanged there until the ungoliant and melkor escaped and the darkness disappeared and it’s net faded, (so it’s still could keep them permanent without the intervention of other valar and all the primordial powers of them were diminshed, were Tulkas could scatter all the darkness before him, yet he couldn't in companion with Orome from freeing themselves and scattering
the shadows therin) , so no point of truth that he is incompetent , nonetheless Tulkas wouldn’t be a match for Melkor in his prime form before he dissipated his power and Tulkas came to the aid of valar , where Melker was able to match 14 of valar that time , until Tulkas arrived and tipped the balance , so Tulkas would be defeated but mostly by many maiars ( like many
dragons and
balrogs and other primal
spirits ,
sauron in his prime form ,
saruman as a
maia but his power is unlimited but for sure not just asimple army , at the same times all the valar lost their power overtime and they weary so even for Tulkas and during the thirs age wouldn’t be as powerful as the time he descends to
Arda , plus the winged dragons were able to let the Valar flee back and those are fallen maiar but not the creation of Melkor , When Tulkas wrestled with Melkor , it’s said wrestled with him not directly crushed him and cast him away and even J.R.R states that Sauron power were effectively better in
first age than Melkor in the
second age , so you could imagine until which level that melkor lost his power to the level that he was at a class the mightiest Valar to reduced below the Maiar level , add to this the same goes to other valar (like Tulkas).
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atop of that being less grade doesn't mean they can't kill you if they overpowerd you , for example sauron destroyed first by man , Azug killed by man which it was fallen maia , ungoliant caught Tulkas and humiliate him.