Was the Council of Trent against the protestants?

Essentially yes, Protestants were branded as heretics.

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Catholic AnswerThe Council of Trent had a two fold aim:

1) to address the errors in the Church's discipline at that time, and to reform them.

2) to combat Protestantism, and to return the people to the Church.

The Council was very successful in its first goal, not so much in the second, in that the people who were lead astray have not been returned to the Church yet.

from A Catholic Dictionary, edited by Donald Attwater, Second edition, revised 1957

The Council of Trent

The 19th ecumenical council held at Trent in the Austrian Tyrol, 1545-63, summoned for the purpose of combating Protestantism and reforming the discipline of the Church; the longest and one of the most important of all general councils. It dealt in detail with the doctrinal innovations of the Reformers and with those gross abuses which gave them an opportunity to take root. It was one of the most important events of modern history and has had lasting effect.