Are you quoting a true recorded history or something else? I know that historians have documented the disagreements between Atse Yohannes and the catholics as well as moslems. But no historian has painted him cruel as you mentioned above. The cross tatoo was also in use centuries before Atse Yohannes.
I have not seen your request for clarification until this stage.
I am not aware that the cross tatoo was in tradition before the era of Yohannes IV. I shall be grateful to know when and how it started,if that is the case. However, History attests that during the 15th century, Emperor Zerie Yacob ( Ge'ez for 'the seed of Jacob') decreed that all christians should wear a neck cross.
As to the character and approach of Yohannes IV towards non-christians, I have quoted from history.Yohannes IV was very often represented for his narrow mindedness and religious fanaticism.He may have had solid reasons for his rigid stance towards Musilms .Some historians contend that the method of conversions he employed involved only force that left no choice for Muslims,but complaince ,in order to save their lives.He ordered muslims to build churchs in place of mosques and to pay tithes to their parish priest.He was not only determined to halt the spread of Islam,but to eradicate it from his realm by any means.
Historical records also show,that he was restrained only when he received a letter from the Patriarch of Alexandria warning him of the dangers the Copts in Egypt would face if he continued to be harsh in his treatment of muslims in Abysinnia.
Today,there are Muslims in Eritrea known as Jabartis who claim their ancestors have been expelled from the province of Tigray(Ethiopia) during the days of Yohannes IV and point fingers at us the Tewahdo Orthodox for the cruelty their for-fathers faced at the hands of the king. Not suprisingly many of them have become Jihadi symphatizers.
You might like to check the following titles ,
i) Yohannes IV and Menelik II: The Empire Restored, Expanded, and Defended; Autor: Paul Henze ,
ii) Yohannes IV of Ethiopia : a political biography --Author: Zewde Gabre-Sellassie