As I said that's incredibly vague. How did he summon Acnologia then exactly? In a previous chapter Zeref said wicked thoughts. Is that then how he summoned him? That "summoning" is very relative.
Zeref punished Hades for 2 things.
1) Making him forget the weight of life and
2) Summoning Acnolgia
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From that page given, it is safe to say the Zeref had once slaughtered many people in different eras, however the war 400 years ago caused him to discover and learn about the value of human life. Hence, Hades also has no value for human life. Since Hades has no value for life, Zeref could have possible saw his old self in Hades thus causing Acnologia to be summoned.
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That page says Acnologia 'once again' disappeared from sight. This may imply that Acnologia was the thing that destroyed 'eras' when Zeref still had no value for life. That is why Acnologia has only reappeared after Zeref forgets the value of life.
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On that page, Zeref states that if he were to forget the weight/value of human life then he should be able to use his magical power the the full extent. Zeref also says Acnologia was summoned due to Hades' evil ambitions.
Now, due to Zeref forgetting the weight of life due to Hades also having no value for it, Acnologia re-appears once again to end the 'era'.